On our last European trip, my husband and I traveled around with 18-20 lbs each of beer steins on our backs. (Yeah, I weighed those babies once we got home.) We knew this going in, and I think we're done with our stein-buying for a while now...(over the years we were too afraid of using our souvenir L and 1/2 L mugs for fear of breaking them, so now we can relax and use them, knowing that we have back-ups!). Ours weren't the fancy-schmancy ones, typically - they were from Oktoberfest, Prague, Andechs, and Augustiner in Salzburg. Over the years and with only a couple of exceptions, the fanciest might have been ~ €20.
Also beer-related: bottle openers (wall-mounted and hand-held), coasters, magnets, keychains, glassware (kölsch, wheat, etc.), taster placemats, tablecloths and 'bar mops'/wiping cloths (esp. Prague! And don't forget your Pilsner glasses...), Christmas ornaments, posters/commemorative books/any cool printed thing, jewelry, clothing (t-shirts, sweatshirts, hats, socks, ID badge lanyards), figurines (metal, ceramic), music (CDs and DVDs), metal/paper/enamaled signs, trays, bottle labels and caps, canvas/cotton/Tivek bags (shopping/tote), pins, large or small souvenir ceramic plates, S&P shakers, a miniature stein for toothpicks/matches, something to use as a pencil cup, cutting boards and other kitchen tools (aprons, mitts), spoons, specialty foods (beer mustards, cheeses, schnapps)...
For instance, if you have Weißwurst somewhere, you can bring home a Weißwurst set - tureen, plates, and/or mustard pots, etc. Also, anything you can use as decoration for your own Oktoberfest or biergarten party ;-)
If I had to carry or pull those steins around...that would have been painful. On my back was no problem. We just had to be careful with our bags and keep the mugs well-padded.
I always travel with a cardboard mailing tube with tightly-rolled bubblewrap inside; use an empty cardboard toilet paper center to extend the length of the tube, if necessary ;-) You never know what treasures you'll come across...
Now if we break any of our preciouses, we'll just have to go back for more ;-)