I tracked down some of the software created by the community to mod Illusion games, and figured out how to use at least some of the features. The Illusion Morpher was already posted on the last page, so I won't attach that one.
SB3Util - Allows you to read and modify .pp files (meshes, textures, etc.)
You must be registered to see the links
Metasequoia - SB3 spits out .mqo files which are used by the metasequoia 3D modelling software, the trial version is a very competent program -
You must be registered to see the links
Illusion Morpher - Allows you to compare two .mqo files to measure the difference and create a .xdiff file. You can then use that file to morph the character meshes inside their .pp file. A bit unintuitive to use. Without premade .xdiff files, the morpher does nothing.
I haven't created many .xdiff files, but I did make one that yields a big ol' fat ass.
F95 tags SB3Utility as a potential virus, I scanned the list of security vendors, only one of twenty gave a virus positive reading. This list includes Google's virus scanning service. Still though, use caution with .exe files that are dubious. there a suites that allow you to run .exe files in a contained environment nowadays.