I have a fixed gear with horizontal dropouts. They are not track dropouts, to remove the wheel you pull it out toward the front of the bike. I am worried that the bolt on the tensioner will slip off the back of the curved dropout.
I have drop outs like these:
http://sheldonbrown.com/gloss_dr-z.html#dropout
These are the most complete selection of tensioners I could find.
http://www.amazon.com/s?ie=UTF8&rh=n%3A3494341&page=1
I was thinking the ones with 2 bolts might work.