The big problem is not accepting 3D, its presenting it properly.
No freely available renderer right now can do it, the big problem is that the 3D presentation APIs are mostly vendor dependent - i have some code samples how to do HDMI 1.4 3D rendering for Intel, its probably different for others.
If you want 3D, right now you're limited to the commercial 3D BD players, or that "Stereoscopic player"