The Tab kernel drivers must exist in binary form in the Android images, but I can't find any source for them. Likewise the binary user-space libraries that use the SGX hw (up to and including the actual OpenGL library) will exist in the Android image, and it's nigh on impossible that source would ever be released for these.

We have an open source kernel driver for the OMAP4 Pandaboard and closed source binary user-space libs, so the question is really whether a kernel driver can be developed for the Tab that uses the same interface as the Pandora user-space libraries.