Well...after a week of updating, registering and reinstalling various things and the like I actually got XSI to work yesterday.
For a brief shining moment I actually used it and even rendered a couple of models that I was able to successfully convert to mesh (which is also ironic as the mesh conversion has always crashed before)--though it was invisible in the game.
This lasted all of twenty minutes and then after the program was shut down and later restarted--back to a stack-hash error which no amount of tweaking, repairing and configuring now seems to be able to fix.
I've run versions 6-7.5 to no avail and it's obviously a compatibility issue with Windows 7 and some arcane combination of update files, vb issues or some other deep nonsense.
I've disconnected from the internet, stopped the firewall and antivirus, run in safe mode, run in compatibility mode, as administrator, prayed and restarted, reinstalled--etc., etc.
This dog just doesn't hunt on my machine--other than doing a full reinstall of the OS and trying from scratch (can't do that).
Just darn annoying bunch of carp. Curse those fish! A lot of carpy stuff for three stinking models...Hulk smash now.
So I was able to successfully mesh a small model Lavo converted to XSI for me and get it to display in game. The ones I converted to XSI and ran did not display as models in the game.
I'm not sure why all of the sudden now the XSI converter works but go figure. It actually began when I used Milkshape's xsi exporter and tried to convert one of those to mesh. The mesh resizer still crashes miserably on launch.
I knew I should have taken a screenshot of the model in it--sigh--at least then I'd have had pictures.