I continued work on the extension wrapping code for OpenGL-ctypes this evening. The arb multitexture and arb window pos extensions both work correctly. I've extended the auto-generator such that we can add custom code directly after the auto-generated stuff to customise operation.
Anyway, the generator module is checked into CVS for those who want to play. It's not based on the ctypes gcc-xml generator, so it's quite crude compared to the core library wrapping. At some point I suppose I should look at whether the ctypes generator can be adapted to provide better base wrappers, I suppose.