Belmont Station or out of the cooler at the pub. Cascade Barrel House sells in the bottle, so does HUB, I am sure there are more places that do I just can't think of any right now and would just go to Belmont Station and enjoy something on tap, do some shopping, and then enjoy something else on tap.
Belmont Station and John's Market are great for selection, though their prices are exorbitant, especially if you plan on paying with plastic. It's not a store, but if you're looking for great belgian-inspired beers in Oregon you should check out Ambacht Brewing in Hllsboro, Oregon. It's a tiny little brewery just a short ride out of Portland on the MAX. Again though, plan on paying with cash or check! Ambacht Brewing in Hillsboro OR