I used about 10 hard drive magnets to hold a 19" drip tray to the side of my kegerator. It is strong enough to support a half-full pint glass, although I don't normally test that! Good luck!
Kegged: Redcoat Strong Cider, Berliner Weisse, Packing peanut malt liquor, IPA Tripel, Diacetyl Guy (Dead Guy clone full of diacetyl, but the wife loves it!), Union Jack clone, Blonde ale, Nut Brown ale
Bottled: Cascadian Dark Ale, Big Poppa's Ghetto Drank, Berliner Weisse, Cap'n's Reserve (Blonde w/ Cap'n Crunch)