The first thing I did on my last trip to London was to head straight for the Science Museum and check out the Difference Engine they have on display there. It was awesome along with the other examples of mechanical calculators and early computers they had in the same room.

I agree thought that first a virtual model should be built, but only if it runs as a physical model of it in 3d, and not as an instruction emulator. Once the bugs are worked out in the virtual model of course a steam powered version needs to be made - at that point I think you could get bankrolled by a museum.