Jonathan, I wish it was the world famous G50-50 like your! Yep it seems those fetch an 8k for a beat up core fairly easy, no?
The one in the photo was a standard G50-01 from a 1986.5-89 Porsche 911 Carrera and stock US gearing and open diff at the time. The car's original chassis was a 74 911s that was nicely converted by means of grafting in a torsion tube assembly. Now in this configuration there was room for this 5 speed, G50.
Believe me, I wish I could have found a way keep the car. It is tragic, really. Good thing is that it found a good new owner that understood what he was buying. Since he was installing a hotrod engine it was necessary for him to reinforce and install an diff and such. TK ended up doing this and here was that result...
If one is at the point where the core gearbox needs rebuild anyways, having the bell housing and input shaft machined down can be done too. The shorter setup allows for lower profile clutch options. Some of which have an easy pedal. Another common to the G50s was updating of the release bearing fork and shaft which can smooth actuation.
I'm more a fan of cutting the gearbox rather than the car to achieve this. I like the idea of maintaining that structured cross member. Welding in a steel plate after cut clearance I've seen done too.
I think you will be very please Andrew.