Rivco makes a highway bar that clamps to the frame. I have them on my 1800c. Minicop had some for sale not too long ago and I bet he still has them. PM him and see if he has them and maybe they will work for you. Good luck.
he was last active may 26, but i pm'd him and emailed him, we'll see what happens. I like those from Rivco, and that's not a bad price for brand new, a little more than the heel rests, but i like the look a lot more...