Go and find the Parallel Maps modcomp. Then merge it with the RFC DLL (no easy task) and get the Viewports code from C2C (which is built upon and requires Parallel Maps) and merge that as well. It is not easy at all.
As for your idea, viewports would not be the way to go about that because their size can not be changed during runtime.
That's not what I said, but it isn't important. If it's too complicated I'll just use ordinary viewports to help with the massively slow turns a GEM RFC would take.