In the grand tradition of mods gone pro, such as Counter-Strike, Killling Floor and that unplayable Doom 2 level with 354 Cacodemons I made back in 1995, fantasy-themed Civilization IV uber-total conversion Fall From Heaven is going standalone.
How so? We don't know. With what engine? We don't know. With which publisher? We don't know. WE DON'T KNOW. We know only that it is, in theory, enormously good news - Fall From Heaven has accrued the kind of status that a good 50% of people you mention Civ 4 to will immediately name-check it, so it's not really a surprise that this is happening. There are any number of specialist strategy PC publishers who would be insane not to pick it up. Trailer of the still-existent mod version below, trailer fans.
Nice snow leopard.