To make it cheaper it'd probably be better getting the shirt and printing/embroidering done at the same place.
CanadaReady (or whoever made the RM ones) will already have a link/contact to do this i'm sure.
Shirts, and Key Rings is a good idea, maybe the RM site could have a shop selling such things! I'm suprised there already isn't a 'Online Shop' page, with mugs, shirts, key rings etc, i think it has been discussed before though.
Obviously seeing as the 'RM AREA' would be part of the site, the shirts could be sold via the online store for anyone who wises to be part of the area OR even in general wear an RM shirt i guess
Excellent idea