Micro,
I have a 4566 (well, two actually). I wanted to dispose of the blued MIM hammer for a hard-chromed bobbed unit.
Look at Numrich (
Numrich Gun Parts Corporation) under 6906. You'll find them there. You will have to cannibalize the hammer stirrup from your 4506 to complete it. The outlay (if you want to call it that) in labor is well worth the time.
Where are you in SoCal. If you're in the I.E., try my friend, Bill Burris at The Shootist in Murrieta. He can do it easily for you.
If you really want to 'pimp' the gun, send your trigger into Mag-Na-Port and have the trigger contoured and polished. The Wilson Combat 17# hammer spring is also a worthwhile modification. The spring and trigger make my 4566 break at a crisp 8lbs DA and about 3.5lbs SA with virtually no creep.
The S&W 3rdGen autos are some of the most underrated guns out there. They are Russian T34 tank-strong and have the short reset on the trigger (10+ years before SIG brought it out).
Hope it goes well for you!
All the Best,
Greg Topp
CWO2/USMC