Well I don't know what exactly what beer mugs that you had in mind but I can tell you what we've brought home with us!
Several of the attraction gift shops carry mugs.We've gotten ones at PoC,RnR.They're around $10.The Germany pavillion in Epcot carries a nice line of imported German steins.They also have a small booth outside that etches Disney characters in glass mugs and can be personalized with your name.