You should be able to pick up a new upper receiver for the 22-45 for about $250. Maybe a little more. Keep the original for a back-up. Cheaper than buying a whole new pistol.

Not an expert on cans, but you should be able to pick up a reasonable can for $300+tax stamp. A user serviceable can is suggested. My .45acp can is serviceable. Once I have it in possession, I'll bring it over and let you take a look. With your skills Marv, I'd suggest going the form 1 route, and build one. Proper tax stamps and such. That way you can experiment with exit diameters.