Not to disagree with you Oz, but we have heard alot of interest expressed about the
Steampunk Mod which is in vigorous development. What we haven't had alot of is unit makers jumping in. There are some legitimate reasons for this: It's summer, we've lost a number of unit makers to Civ4, a few have said they'd like to finish their current projects first. But since you've opened the discussion (with an excellent idea, by the way), let me point out that there is some work available for unit makers who aren't necessarily comfortable with complex units. For example, we need a Jules Verne - style moonship made along these lines:
and a Tardis (yes, from Dr. Who) for which we actually have a blender file:
If even these are too challenging or time intensive, we are also looking for re-colors on a few already existing units.
If this interests anyone, come on over to the steampunk forum, where you'll be very welcome, and help us make a truly unique and interesting mod.
And thank you again Ozymandias, for your interest and support (and a good idea!).