No one on the islands, that's depressing. In answer to your question, here's the best, just Google:
Hamilton Bowen Classic Arms
Cylinder and Slide
David Clements
Andy Horvath
Alan Harton:
[email protected]
http://www.gunblast.com/AlanHarton.htm
http://www.gunblast.com/Harton-No5.htm
Gallagher. His prices are very reasonable also. http://www.gallagherfirearms.com/ Great guy to deal with.
Ben Forkin (http://www.gunblast.com/Forkin44Vaquero.htm)...
Vans Custom guns over in Sandusky, Ohio.
Actually in your situation, the most cost effective solution is to sell your gun and just buy the short barrel model, you'll be time, hassle and money ahead!
If you still want to cut 2.5" off, you might as well get the extra long Ejector rod and housing too. It'll knock the empty cases all the way out of the cylinders. If not cut it all the way to 4 5/8" like the factory short barrel which is even with the end of the ejector and make it as compact as possible.
But that's such an easy job you could do it yourself if you're the least bit handy. And save about $250 in labor and shipping fees. Get a hacksaw, a fine mill file and a 4 flute countersink bit for your drill to crown the muzzle; once the cut barrel is trued up square with the file. Buy a new sight from Ruger and a sight screw. If you don't drill and tap holes, any machine shop can do that. By screwing the sight on, you won't have to reblue the barrel like if it was soldered back on.
Let us know how it turns out.