One of the microbreweries I visited in Munich had the tap directly hooked up to the brewing tank. Unfiltered godlyness.
Majestic, the wine people, tend to sell 12x500ml of it or the Oktoberfest version.
Reminds me of a time when Martin (joint owner of Brewdog) was testing some beer in one of the fermentation vessels. He put a glass up to the wee side tap about 1/3 of the way up the FV and turned it on. Queue the valve coming off in his hand, and beer (which was under pressure) went spurting all over him and the brewing floor. It was like something out of a cartoon, with him looking around anxiously before trying to put his thumb over the hole (which obviously failed, and ended up with more beer going everywhere).
Being good employees, myself and another brewer just stood and laughed at him.