I have not seen any circular DB patterns. (That doesn't mean they don't exist, however.)
Her patterns and books look lovely, but the patterns are not particularly well written, in my opinion. I hear lots of people complaining about how confusing the directions are. I'm an experienced knitter, and several times I've had to punt, just doing what I thought she meant. If you're a newer knitter, I wouldn't recommend them.
You can also convert some of the patterns to circular. For a pullover sweater, just cast on the number of stitches required for both the front and back and subtract four. (These stitches would have normally been the seam allowance.) Have you ever seen the patterns here: http://www.littleturtleknits.com/pages/patterns.php ? They are EXTREMELY user friendly.