I've got a rotating-table laser scanner (Roland LPX-60) I can sell you for $7k. It would work fine for this project. I'm not sure about your rubber sheet idea, though. It might make more sense to take it to a vacuum former and have a plastic sheet drawn over the gun; then you'd have a permanent thing to scan that wouldn't snap back as soon as you released the vacuum.

It shouldn't be too hard to make the changes you're talking about in Solidworks. Just superimpose an appropriately-sized cylinder over the notched one in your scan, and save the composite as an STL. You can model up a block that fits the trigger guard and treat it the same way. Or if you're going with the vacuum-forming idea I mentioned above, just fill in those areas with clay or something before you do it.

Andrew Werby
www.computersculpture.com