I brewed a kolsch earlier this year for my Oktoberfest party in the Fall and it is pretty good. Like Joos said, not an end-all-be-all style, but refreshing and easy to drink. Shouldn't scare away the non-craft beer drinkers at my party. I used White Labs WLP029 Kolsch yeast (an ale yeast) and fermented at lower temp (60-62*F)hoping to get a more lager-like characteristic, which it did. It's a little sulfery at first, but they say it should go away with some aging. As for a commercial version, I haven't had the pleasure yet. There is a new local brewery with one on tap, but haven't made it in there since they opened (have a 2yo and 6 week old at home, busy!). From all I've read, it's about the closest you'll get to a clean lager by using an ale yeast under ale yeast like fermentation conditions. Good luck with your search and let us know if you find a really good one you like.