Theoretically it could be done. I looked into something like this last time I used Millenaire and didn't see anything that would stop it other than block ID problems. I don't know if anyone has ever designed a Millenaire Civ to use blocks from another mod though.
From my understanding of Millenaire, the only blocks the villagers actually "use" (as in, actually interact with) is chests - everything else is just blocks being removed or placed while villagers stand next to them looking busy. As I'm writing this I've become uncertain as to whether they actually "use" furnaces, though - my initial thinking was that all of their crafting was done via "transmuting" the base items once they're in the village's system, but I think I remember them waiting around for things to finish smelting.
In any event, it would be probably pretty straightforward to let the villagers sell various Industrialcraft-type things, and place various machines and whatnot in their homes and workshops. The buildings would be downright easy, in fact; I'm pretty sure there's a very accessible tutorial to creating custom buildings for Millenaire somewhere out there. Actually properly utilizing the machines, though, not so much I think.
Still, it would be pretty awesome to see someone make a crossover along these lines.