Let me just get this out of the way: turn-based isn't fast and it doesn't sell.
Other than that, sounds cool.
Turn-based sells just fine. If it didn't, Square wouldn't be releasing two additions to the Final Fantasy Tactics line, Advance 2 (on GBA) and a remake of the original Tactics (on PSP). Firaxis and 2K games wouldn't be releasing a secon expansion for Civilization 4, either. Games that don't sell don't have a habit of getting sequels, expansion packs, and rereleases.