A ranged rogue on the back lines is somewhat possible if, counter-intuitively, you stack him up with str. There are no hit/miss mechanics for ranged weapons, they always hit. But they don't get bonus damage from dex, at all, so apart from evasion, dex is useless for a ranged character. Str, however, adds to both throwing as well as bow/crossbow damage. So a full str rogue minotaur is the best choice for a ranged character, though he'd suck enormously when put in the front line.
I think I'd rather have a back-up melee rogue with 12 assassin skill and daggers though. In case of emergencies, he can tank for a few hits, and in any case, he'll do pretty damn good melee damage, backstabbing from the second line.
I first had a normal warrior and a minotaur warrior in the front lines. The minotaur, with less dex, was getting hit all the time, while he couldn't hit the broad side of a barn with his club. As already stated in this topic, clubs + minotaurs is a terrible combination, and I've thrown him out after a restart. First time around, I also had a full dex ranged rogue, cause I thought dex would do something for ranged damage/hits. And I picked magic haphazardly depending on whatever spells I got first. All in all, my first party sucked pretty badly, only my heavy armor sword warrior did well at surviving and hitting things.