Do you think it would be possible to also have the original version of the shuttle cockpit?
Yes! The central issue is: how to drive all those meters and gauges? The current logic is a very hacked MEDS, with lots of shortcuts in the data flow, which won't really work with those displays, so there is still a lot of work "reworking" code to have a more correct relationship and interface between the components. Once done, the IDPs can be replaced with DEUs and (the original) DDUs, and they will respectively drive the DUs and some of the meters, and the MDMs unplug their outputs from the ADCs and plug into other meters, and done!
(plus some hopefully small GPC code changes)
Some of this "invisible" reorganization work has already been done, other parts are ongoing and more will come in the future.
How about getting rid of the "cheaty" method of illumination (using material emmisivity) and using proper light sources? Then this would be a thing:
https://www.orbiter-forum.com/threads/orbiter-screenshot-thread.8/post-579680
Years ago, as a proof of concept, I did light the vc with internal lights:
The issue is handling the variable brightness panel backlights, push button indicator lights and (simple) indicator lights. The D3D9 emissive textures should help, plus whatever is being done in the DG, but even if that gets solved, there is still the big one: internal lights would be adding (I think) 13 more lights to the scene, which means you have to choose between light inside or light in the PLB, which would make for some interesting RMS operations in the night side. Oh, there are more lights in the middeck and airlock...
Also, if the lights don't point at some object, then they are dark, so the graphics engines would need to have the light bounce from lit objects, thus spreading it around the scene, as it happens in reality. AFAIK, there are no lights aimed at the overhead panels, so they count on the reflections (lights and Sun) to be seen. Light shadows would probably also be needed, so only light coming in thru the windows has an effect, e.g., PLB lights having a limited effect inside vs blasting the panels with light.
It would look definitively awesome, but the current graphics just don't support the level of lighting needed to make it work in the complex internal/external light architecture of the Space Shuttle.