Big River should have a 'beer flight' sampler ... at least they did have one a few months ago. As mentioned, the biergarten has one as well.
I 've heard that Rose & Crown pub in Epcot's WS also has a beer flight/sampler, but I can't confirm that personally.
The best beer (in mine and most beer lover's opinions) in all of WDW is available at Le Cellier, which is very difficult to get into. If you do happen to get a LC reservation, check out the Unibroue brews, especially the Fin du Monde and Maudite.