A 
[Stealth] run is typically conducted with only Rogues and/or Druids in the party. The idea is to stay in Stealth, sneaking through the entire instance to the target Boss, kill the objective(s), then re-stealth and sneak back outside.
Note that "skull" type bosses scale with your level. In recent patches, these have all become more difficult. Roccor and Razorlash are probably still doable. The jury's out on Celebras. Plugger is generally considered a duo mob at present -- bring a friend (or a greater shadow protection potion which makes him quite soloable).
Tips and Tricks
- Not all of your Group could have or have skilled the + Stealth Talent. So the Sneaking Potion comes very handy. Rogues could use it in stealth, Druids must shift out and drink and restealth.
- Sometimes a Rogue kiting some mobs and a "magic" vanish helps a lot
- Stealth is to slow? Use
[Shadowstep] to "jump" through the instance - Sapping one or two "Guards" helps sometimes.
Soloable Bosses (lvl 70)
- Hellfire Ramparts (normal)
- Omor the Unscarred - Medium Difficulty - feral druid. Stack stamina/shadow resist gear. This fight is about outlasting his 60k health. Swipe adds as they come. If your health is high enough, Imp LoTP should be enough to hold your health with an occasional Frenzied Regeneration.
- Vazruden & Nazan - Medium/High Difficulty - feral druid. Either go full cat DPS gear, or stack stamina/fire resist for a longer but safer fight. Pull 2 guards back to brazier across bridge, and when guards are dead stay there until Vazruden dismounts. He will then not aggro, while you attack Nazan. Nazan has 3 points from which he shoots fireballs at you; you may safely attack him from the ground from two of the 3 without aggroing Vazruden. Once Nazan drops, Vazruden is a simple fight in bear form.
Stealth Bosses (lvl 70)
- Sethekk Halls (heroic and normal)
Note: since 2.1 you need one Rogue to kite Darkweaver Syth to one edge of his room to let the Druid sprint/dash throu.
- Talon King Ikiss - 3 Chars minimum (2 Druids + 1 Rogues) Drops [Shoulderpads of Assassination], which is great for both feral druid and rogues.
Note: You could kill all Bosses with (2 Druids and 1 Rogue). The only tricky fight was The Beast and General Drakkisath. Our "heal" Druid was balance specced and done some damage too, Killed all Bosses in first try.
- Pyroguard Emberseer - Easy fight you need 3 people to summon
- Solakar Flamewreath - Easy too
- Goraluk Anvilcrack - Easy
- Gyth & Rend Blackhand - Medium
- The Beast - Difficult, because you always in fear and most time cant do anything except running.
- General Drakkisath - Difficult fight. First you should kill all Groups after the Bridge. After that your Tank should have some Fireresi on. (not quite much but some :D). Tank should gain aggro of General Drakkisath and its adds. Focus tanking and killing the adds first. Only the Debuff [Conflagration] is a bit heavy but manageable.
Soloable Bosses (lv 60)
A lvl 60 rogue or druid can often solo these.
- Lord Roccor - Medium difficulty for 1 rogue or 1 feral/restoration druid
- Plugger Spazzring - Medium difficulty for 1 rogue
- L70 Feral Druid- no trouble soloing these bosses in addition to Lord Roccor and Plugger Spazzring
- Razorlash - Easy for 1 rogue
- Celebras the Cursed - Medium difficulty for 1 rogue
- Rotgrip - Medium Difficulty for 1 rogue
- Princess Theradras - Extremely difficult for 1 rogue
Stealth Bosses (lv 60)
- Lord Incendius in BRD
- Easily done with 1 rogue + 1 druid. Due to a debuff Incendius gives, Fire Resistance gear is near useless.
- Lethtendris in Dire Maul East
- Difficult with 1 rogue, doable with 1 druid and 1 rogue.
- Mother Smolderweb in LBRS
- Difficult with 1 druid, doable with 1 druid and 1 rogue.
- Mor Grayhoof (and War Master Voone) in LBRS
- Difficult with 3 druids, doable with 2 druids and 1 rogue.
- Shadow Hunter Vosh'gajin in LBRS
- Requires minimum 2 well geared rogues and 1 druid. Vosh'gajin and her 2 priests frog melee attackers and go after the healer. Stuns should be used where possible to prevent frogging. A fast run of Vosh'gajin can take as little as 15-20 minutes.
- Morphaz in Sunken Temple
- Very tough for a single rogue, even fully buffed at level 60. Morphaz has a bigger and stronger friend named Hazzas and can't be pulled separately. He's also immune to poisons and stuns. He's fairly easy with two 54+ rogues; take him down fast and then [Vanish] if necessary. After Hazzas leaves you can loot Morphaz. (This is a fast way to get [52D] The Azure Key for rogues that have picked up the quest.) Buffing with a [Nature Protection Potion] is highly recommended.
- Very tough for a single rogue, even fully buffed at level 60. Morphaz has a bigger and stronger friend named Hazzas and can't be pulled separately. He's also immune to poisons and stuns. He's fairly easy with two 54+ rogues; take him down fast and then
- Razorlash in Maraudon
- Difficult with 1 rogue or druid, until greater gear is obtained. Easily Doable (level 60), no matter the combination.
- Princess Theradras in Maraudon
- Extremely difficult to solo as a 60 rogue (/w 8/8 T2). If you intend to solo this boss, use as much self healing items as possible ( [Darkmoon Card: Heroism], Bloodfang Armor, Lifestealing, Crusader). [Nature Protection Potion] also help with [Dust Cloud]. Fight becomes very easy with a Druid healer.
- Extremely difficult to solo as a 60 rogue (/w 8/8 T2). If you intend to solo this boss, use as much self healing items as possible (
- Plugger Spazzring in Blackrock Depths bar.
- Requires Shadowforge key or high level lockpicking by a rogue. Buy beer from Plugger, stand by Dark Iron faction guy, place a beer at your feet. Kill the bar patrons when they come and drink it until plugger stands alone. Shadow and Fire protection potions makes it easy.
- Pusillin in Dire Maul.
- Difficult as a rogue or a druid - stealth naked, talk to Pusillin 4 times (and die almost certainly each time). Then he will run upstairs to a platform, where you can talk to him the 5th time (run away quickly). You will be followed by 5 little imps, which you can mill down one by one until (prepare to die once unless you're a really big bear). If you can get him alone, he's a mean fire damage guy, wear FR gear and take a potion. He drops [Crescent Key].
- Difficult as a rogue or a druid - stealth naked, talk to Pusillin 4 times (and die almost certainly each time). Then he will run upstairs to a platform, where you can talk to him the 5th time (run away quickly). You will be followed by 5 little imps, which you can mill down one by one until (prepare to die once unless you're a really big bear). If you can get him alone, he's a mean fire damage guy, wear FR gear and take a potion. He drops
[52D] 
Other Stealth Runs
- Mining Dark Iron: Dark Iron stealth guide - Close to impossible after patch 2.1.0 due to mining aggro.
- Scholomance: Scholomance stealth run
- Attunement to the core
- 2nd/3rd Fragment Attunement
- Stealth Chests
Interesting info on lethendris & incendius : http://www.roguespot.com/guides/AMR1.htm
also see: Rogue Solo List