One thing to note is that, as far as I know, if we would switch to omapdrmfb, we should abandon the fbdev driver. Replacing it with xf86-video-modesetting or something similar (which is now part of X), if we then implement the right dri/drm API calls from the closed blob you mention, we should get 3d for 'free' (not really for free at all, just that we'd be using the api that others also use for 3d on modesetting -- radeon and nouveau I think).