Has anyone found any good reference pictures? Any ideas on the colors for the interior?
Also, I think I read that this tank was used by the Isrealies at some point?
Any one care to comment on the Tamiya kit? Rob?

Charles, Are you referencing the assault gun version? If so, I can send you some good info I gathered from various sources. Send me a PM if it's the assault gun.

Generally, I think the Italeri version is superior in detail and craftsmanship to the Tamiya kits of both the 75/18 M40 assault gun and M13/40 tank version. Also, if you can, get the ModelVictoria individual link tracks. Easy clean-up, easy and quick build, and look super. My choice for best aftermarket tracks.

I second Bob's words. The Zvezda (using the Italeri molds) Semovente is generally more accurate than the Tamiya one. I have a number of Model Victoria products and they are all excellent. I am using their tracks for my M13/40. I would also recommend their Semovente M40 Conversion Kit. It would include extra details and stowage, as well as make the model a real 1940 model, rather than the 1941 model that really comes in the box. Both Tamiya and Zvezda share this problem with their M13/40 and M40.
I wouldn't worry too much about the interior, any light buff colour should do.
I'll check for some good reference pics when I have more time, but one tip I can give you is to check pictures of M13/40 medium tanks, as the M13/40 and M40 share many features, the Semovente being built upon the M13/40 chassis.

Nic