the idea I think is to make a second game based on Dominions, but what I'm thinking is a second game within Dominions
It would best be done in a way that allowed a smooth translation from turn-based to rpg, so the commander you put in your dungeon-site would have a strong effect on the rpg, either overseeing the effort/support system and probably leading the party, or just the commander and no party. Either would be fine with me, although I think it would be interesting if logistics and management/strategy were a vital part of the process, so that you have a kind of "archaeological dig" in the modern sense, only you have to worry about creatures and traps and getting dropped in the Inferno, not to mention your "dig" being overrun by the other Nations ala Raiders of the Lost Ark. The whole thing could be done in stages, instead of running madcap into a dungeon and attacking it like you would a fortification, you'd be presented problems at each stage-one month you have to deal with a magical lock, the next month with a powerful Cthonic demon and his followers who have been trapped down there for millenia, the third month you have to do maintenance/repair on the dungeon, shoring up the walls and bypassing a waterdamaged wall that just might be a deadly watertrap. I think it could end up with a "feel" somewhere between Indiana Jones and the X-files, combined ofcourse with a Roguetype, while still being a strategy-based, methodical process who's results might easily impact the greater game.