You are correct in your second statement. The nVidia GRID (VGX) technology is a fully capable vGPU channel into a supported nVidia GPU that has full support for all DirectX and OpenGL extensions. The only offering Im aware of that will fully utilize this technology is Citrix XenServer with XenDesktop. You can find more information about this here http://www.nvidia.com/object/grid-software-partners.html under the "virtual desktop solutions". Citrix's solution is not yet publicly available.
Regards,
Nathan