Daniel
thanks for doing all that research. i'm going to post my proposal for the color-space stuff in the next 24hrs. basically i'm going to suggest that the start of the chain sets the format and conversion is done only in special cases (i.e. no auto-conversion). i'm also going to propose a system for proposals!
This introduces the more general problem of how to handle openGL extensions under GEM. At the moment extensions are handled at compile time and in a fairly ad-hoc way... perhaps something like GLEW would be useful (altho it doesnt support OS X)
we already do this on OSX. we have some sgi code that checks for the string in the driver. it's very simple and should be cross-platform.
cgc