Sounds like a good idea to me, but judging from the speed Illustrator renders, I''d say it''s a bit processor-hungry. You could probably do it if you only used straight vectors (no curves) and wrote a texture mapper that could fill polygnos with as many sides as you want (so you don''t have to draw a million tiny triangles for a semi-smooth curve), and then draw greyscale alpha-blended triangles over that for shading, which you could do with hardware to (maybe) get a reasonable speed out of it.
-Deku-chan
DK Art (my site, which has little programming-related stuff on it, but you should go anyway^_^)