You can get the plastic rollers from most any Tbird parts stores listed in the Advertisements Forum. For Brass ones, here is some additional information for you.
Sources for brass window rollers.
Check with CASCO. They used to have the metal window rollers. Their information regarding these parts state they are made of metal for the CASCO one. As for the size, they are stated to be the same size as the part #'s given for our Squarebirds. (Part# 23240) BA-7023240-A for the '58-'59 and C0AB6423240-B for the 1960 Squarebird. The unit that CASCO sells for the '55-'57 Tbirds (which also fits the '58-'60 Tbirds) is 23240M Description Window Roller-All Metal. email@example.com
. 800-374-0914. Check with Fordcraft ~ '55-'57 Tbirds and National Parts Depot - '55-'57 Tbird Parts, Tee-Bird '55-'57 Babybird Parts also.
Check with Martin ~ 60 T-Bird. He was gearing up to produced these brass rollers for us. I do not know if he did or not. http://squarebirds.org/images_WindowRollers/