If you like the Kink Curb, look at the Kink Gap or Gap XL. The Gap is just a tad bigger than the curb, and the Gap XL is a little bigger than that. There are plenty of bikes in your price range with a 20.5-21 inch top tube. No matter what you pick, you'll love it, but at the same time, you'll wonder if you should have gone with something else. It always goes like that.