Kevin Caccamo has updated his OBJ2WCP program that imports OBJ files into the Vision Engine. Some Prophecy/Secret Ops modding experience is needed to understand how it works, but some basic instructions can be found here, and the new 1.1 version of OBJ2WCP can be downloaded here (16 k zip).
Update: Objects converted by OBJ2WCP now render properly in-game! I'm trying a bunch of different algorithms to calculate the unknown1 value. Let's see if this one doesn't totally eliminate the disappearing faces problem. Here's a screenshot of my WCUE mod, featuring a Scimitar cockpit converted by OBJ2WCP.