Found an old project of mine(2006) for the original psp. It's a full 3D engine, and while I cannot remember all features, it can do quite a bit.
It's a single source file, but a full engine. it includes some demo code.
It obviously requires a modded psp, but uses the open source pspdev toolchain. feel free to use anyway you wish.
(Sorry if this isn't appropriate for this forum, feel free to delete if so.)