The version of the SF4 Viewer that is most widely used is 0.33, but piecemontee made some significant strides since that release and has since released another stable version (0.35) and an unstable beta (0.36ik; you can get these and other versions here). From piecemontee (regarding the unstable version):
[I]t includes preliminary animation display (open up .cmn.emz / .cos.emz and .col.emz then go to the EMO model to see a new combo to select the stance)
I tried to display BCM input commands as well but I don't remember how far I got I planned to allo input commands edition
Warning this version is buggy as hell and if I remember well you cannot resize the window after loading a model
Here's a screenshot of the animation viewer in action:
Yeah, it's a little fucked up, but it's a start!
In addition to these newer versions, piecemontee gave the modding community the best gift anyone could ask for: he opened up the source code for anyone to work on or add new features! The program uses DirectX 9 and pure Win32, so anyone who has experience with these APIs can head on over to SourceForge and check out the code, via mercurial.
Piecemontee told me that he doesn't have the time nowadays to continue hacking away at the SF4 Viewer. However, now that the source code is available, there is the possibility that someone will modify it to work with assets from Super Street Fighter 4 on Xbox360. According to a post over at the XeNTaX forums (from this thread), all it probably needs is for someone to switch the "endianness" (from big to small or vice versa, I guess) and it will be able to view/import things just fine. At that point, we should be pretty close to importing assets from SSF4 into vanilla. :D