Andrew had started implementing assimp but had issues with getting the animation portion working a while back.
I took a look at it myself because assimp support is on the docket for 4.0, and had integrated it into the ShapeAsset for loading. Got mesh loading fine and had been looking into the animation side(got it mostly figured out, but not 100% done).
I'll get the code I had for that and toss it into a branch for you if you wanted to poke at it. If we get animation loading sorted, it's mostly done. The odd part comes from how the different formats store their bone transform tweens.