A couple of points to make here...
1) I'm seriously jealous of this guy with his mint Medalist! ;-)
2) Try Vitarbo grips (retailed by Nealj guns www.nealjguns.com
3) The Medallist/Challenger frame is pretty straightforward to fit grips to. It doesn't take a whole lot of woodworking expertise to make a set to fit. I've done this for Ruger MKI and MKII using birch, cherry, and maple - started out with making a set in pine so they'd be easy to carve. If your friend has access to a Dremel tool, a reasonable grip can be made in a couple of evenings.
Glad to hear there's still some shooting going on in the Montreal area.