I think it wouk look fabulous, especially in a vintage bathroom! What would concern me is the moisture would cause rust. Perhaps a couple coats of polyurethane would do the trick.

hi there there is something out there -its vinyl tiles that look just like tin
here is a website that has what im talking about - i think Home Depot sells it too - my dad acutaly has it for his backsplash in his kitchen

http://www.armstrong.com/resclgam/na/ceilings/en/us/metallaire-metal-ceiling.asp

Here is a link that might be useful: vinyl tin tile

Just finished up tin ceiling tiles for the same reasons as yours! I don't have pics yet, but it came out excellent. You do not have to worry about rust as everything is powercoated. They told me if we really want to, we can caulk, but it is really not necessary. We do need to caulk the corners in the crown moulding.

See www.americantinceilings.com. They were very helpful.

We did pattern #20 in bright white satin in a 37 sq. ft. bathroom. We've got a retro/beach thing going.