41 Mag barrels and cyls aren't hard to find, on the forum and the auctions. The easiest way to get a bead front insert to pin in your stainless front sight base is to get the 10/22 Ruger bead dovetail front sight and grind the bottom to match the shape of the bottom of your existing ramp sight blade. Then insert it, drill thru your front base pin hole and pin it in place. See here: http://www.brownells.com/rifle-parts/sights/front-sights/sight-bead-front-sku780010042-12134-28847.aspx?sku=780010042
The blue barrel doesn't have a pinned front blade so just grind off the front blade and file a dovetail in the base for the above bead sight dovetail.
I would do my own work. I can buy 2 or 3 guns for the price to have Bowen do it. So who you choose to have it done by depends on how much you want to spend. Just google and shop around; here's a list of the most well known and respected:
Jack Huntington
John Linebaugh
Hamilton Bowen Classic Arms
http://www.bowenclassicarms.com/
Cylinder and Slide
http://www.cylinder-slide.com/
David Clements
http://www.clementscustomguns.com/
Andy Horvath
Diagonal Rd. Gunshop
14131 Diagonal Rd
LaGrange Ohio 44050
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
NIGHTOWLS 1996, Utah: http://nightowlsgunsmithing.tripod.com/index.htm
Alan Harton:
[email protected]
http://www.gunblast.com/AlanHarton.htm
http://www.gunblast.com/Harton-No5.htm