For what it's worth, the last solo campaign I ran had this very concept in mind. My player and I thought it would be interesting to play a band of monstrous/"evil" PC's as typical heroes.
The party was gestalted thus:
Drow Female Sorceress/Favored Soul of Eilistraee
Duergar Monk/Psychic Warrior
Goblin Druid/Warlock
Gnoll Barbarian/Rogue
The story went that the Drow ran away from home and brought the Gnoll with her for protection. They formed a fast friendship not unlike Fafhrd and the Grey Mouser. On their journey surface-ward, they encountered the Duergar; the Duergar left his clan to gain power with plans of going back and conquering his home city. When the three got to the surface, they encountered the Goblin; the Goblin was the medicine man of his tribe until the tribe ousted him in favor of the Orc God, and were ready to lynch him, were it not for the PC's intervention. The goblin joined out of gratitude.
The four heroes arrived at a small village on the outskirts of a broken land, the last vestige of civilization before a wasteland of barbarians and a mountain populated with dragons, or so they said...