I'd like to know the answer to this as well, I'm currently preparing for a thesis concerning 3D graphics and wanted to keep the software part as platform independent as possible.
So, naturally, I was delighted to see there was indeed OpenGL-support in Nvidias Linux drivers (ATi I think supports only the 2D part under Linux which really is a shame). This way I can develop and test using my favourite development environment and can still deploy the final results to the Windows platform
I know that using CG one can program the vertex/fragment part but I'd like to try out all possible concepts so it would be nice to have the support for the OpenGL shading language as well.
Ati seems to supply this at least on the Windows platform (going by their website) but the Windows drivers for Nvidia do not report the necessary extensions, so I guess even there it's not supported yet.
So concluding it'd be a really nice additional goodie to have, so maybe if enough people want it...