i've seen and heard of NSX theft recovery shells with suspension and a few random parts still attached going for under $5k so i'd say the build could be done for quite a bit less. If I were to do it, i'd just get a K20a3 w/ 5 speed gearbox (doesn't even have to run!) as cheap as possible to do all the design & fabrication work with and once completed start looking for sponsors willing to build a K20/k24 turbo 6 speed to swap in it.
I'm thinking you can remove the rear suspension completely from the NSX and replace it with the frontend components of the RSX/SI, obviously removing the steering rack and having to weld in new shock mounts, etc. I haven't researched or compared axle width yet but i'm sure they're pretty close and could easily be tweaked with a little bit of ingenuity.
I honestly think it's a feasible project that is not far fetched. 4 cylinder transverse mounted mid engine car, it's not like it's the first time it's been done
