Found on EW.com:
Any chance you could find the undershirt worn by Hugh Jackman as Wolverine? — Chris
The X-Men prequel won't even hit theaters until May 1, but the trailer has already clawed its way onto the pop culture radar. Costumer Louise Mingenbach chose "Richelieu'' ribbed tanks by Swiss brand Zimmerli ($77; customshirt1.com) to show off Wolverine's buff arms because she liked the top's ''traditional look.'' Mingenbach had each tank aged to a different level of distress, using about 50 in all. We hope she saved them to sell on eBay later.
Another source for the Wolverine Tank Tops: hisroom.com