[Faceman]

If you're talking rogue and meaning THIEF I can imagine soloing without too cheesy tactics and completely without cheating.
Ignore lockpick/pickpocket/detect trap skills and concentrate on stealth and set traps.
Typical thief tactic is to hide in Shadows, backstab, run away (even without Speedboots this can be accomplished if you manage to hide behind a corner or a door and hide in Shadows again fast enough) hide in Shadows again and continue backstabbing (you could also use Invis. Potions, but you just don't have endless supply of them).
For creatures immune to backstab (Beholders, Dragons Golems) it is -> set a lot of traps and lure the foe to them to take him out (if you don't want to set them at his spawning point, which would be cheesy tactic again).
Mind Flayers (even Ulitharids) can be killed with one critical backstab hit and mages do stand a chance if you just hide and wait for their protections to wear off.
Soloing with a mage does not seem any problem to me, as you can take out everything with the right selection of spells (However this involves a lot of resting for memorizing AND constant reloading and intelligence boosting with porions to make sure you copy every spell you find to your book)
If rogue means BARD however I can't really imagine a solo, as the wizard spells are too weak and the melee performance is bad too. You could excel as a Jester by letting all enemies slaughter each other through your confusion song, but I don't think that would do you any good on Eye Tyrants or Dragons who tend to be rather lonely