I need a source for vintage linoleum flooring  

Marmoleum
Why not just go with them? Not vintage but still doing the same as they've always done.

this site has links to quite...
this site has links to quite a few sources for that sort of thing:
http://retrorenovation.com/

.
Marmoleum is still made the way it always was. Could be the closest to
vintage? The fact that it is a solid sheet makes it great for a bath. Thick, strong
and a bugger to install. It is softer than the tile goods you have seen. The
linoleum squares. Somehow it is a bit warmer to the touch, like cork. Worth a
look. I love it.
How do i know? I've got a big fucker of a roll in my garage that i'm tired of moving
around.
I forget where it is made. Over-the-seas somewhere, but we can get it easy in NY.
.

oh.
If you mention where you are located that might help.
Second Hand Rose in NYC has true vintage pieces i think, but expensive.
Not impossible for a bath though. (Smaller sq ft. needed)

I love Second-hand Rose!
I got some way cool vintage modern wallpaper from them.