I know there are several threads on here concerning running the blender 3D package on the N900. I used to run it on a (much slower/less ram) winMob HTC Universal.
Also, when the Amiga emulator is complete, that might give you access to Imagine, Lightwave, Real3D , Caligari and Cinema4D.
Obviously a native app would be much faster. But lightwave would be cool
I just found an interesting question on the POVray newsgroups:
Would it be possible to run a raytracer on a cellphone?
since POVray already runs on Linux, would it be possible to port it to Maemo?
Regards
Aydan