Must it be wood?

If you search the internet you should be able to find the autocad (?) sketches to 3D-print the parts you need.

Ja, it needs to be wood and preferably walnut like the early sporting versions came with. It's to make the gun into something along the lines Mossbergs range of Retrograde 500s. They are dollied up to resemble their old military and police issue guns. The big distributor Lipseys is famous for their exclusive special editions and had a run of 930s made along the same lines. I'm going for something that looks like the one below with the plastic furniture below that.

Only practical advantage that will come from it is that I'd likely get a longer LOP as the sporting guns typically had. So its purely for aesthetics for me.

I the likely event that I don't find what I'm looking for i will buy a suitable rifle blank and try my hand at making one with the tupperware as a pattern   

Would be interested in looking at old furniture from other semi auto shotties too as It's possible that I could modify to suit.