I've done mixed fermentations with Kolsch yeast for Cream Ales and Bière de Garde. Essentially the White Labs Cream Ale blend. (WLP080) I've used it alone in a dark bock - Anchor Steam does this for a spring release. I've also done it once in a Baltic Porter for a sort of "Cali Porter."
It's a useful yeast, and I think it should get some increased play amongst home brewers that want to brew something besides an Anchor clone. Experiment a little, but I don't know that I'd bother trying to brew Euro lagers with it - people will end up comparing to super clean yeasts and saying that you didn't quite get it right. Beers with a little more flavor work well, I could see maybe an American Amber Ale getting the hybrid treatment, or even a Czech Pils?