Marlin probably would not convert to another caliber. Even if they did, the STICKER SHOCK would amaze you. I had ideas about re-barreling, re-stocking and re-finishing an aged 39M to a 1897 (straight stock, 24 inch octagon barrel) and got a real surprise. (Ruger is almost as bad!) Trade for or buy what you want...It's a lot cheaper and way less time involved. Gunsmithing can get real expensive, real quick! and the results aren't always guaranteed.
You might consider that someone else is dying to have a 41 Magnum Guide Gun. While they didn't make many 41s, I have only seen 1 in the last 10 years. Run an ad here or SASSnet or singleactions and be amazed at the number of people who want it...and the Cowboy Shooters aren't shy reaching for their wallets if they see something they like!
Slightly Off Topic. I commented about some bullet moulds on some forums and got a bunch of people who wanted what had been sitting in a box for 20+ years. Also some used Ruger XR3-RED grip frames got traded for something else ...or yankee dollars.
