So I wrote a converter for .3do files that produces the format our engine expects (Collada plus some custom XML) and tried some units from BA:

(click for bigger view)
(Is there any way to extract animations as a series of keyframes? I've not looked in much detail but all I see is COB scripting stuff which I don't really want to touch. It'd be pretty neat if we could just get some basic walking and attacking and dying etc animations - currently I'm stuck with static meshes.)
Unfortunately I'm not sure what the point of this is. It'd be intriguing to reuse some Spring mod content for experimental 0 A.D. mods, but our engine isn't quite mature enough for that to be sensible yet. Maybe conversion in the other direction would be interesting or useful for some people (all our art is CC-BY-SA and we're happy for it to be reused). Anyway I think it's fun to play with this stuff, and it's nice to look outside of a single project occasionally, so that's good enough for me.