I have done something much simpler for my Evo:
www.surfski.info/forum/1-general/19650-t...oot-strap.html#34990
It's two velcroed pieces, one attached to each side of the boat and hooking on top of one another. Made from straps that Ikea used to package a mattress into a roll.
It's not padded and I wish it was more rigid so I can put my Gramin eTrex on it, but on the plus side I can make it pretty snug and it conforms to my feet without causing any discomfort.
Since posting the above thread, I removed the orange loops as it was causing too much sag.
Replaced the original strap on my GPS watch with two vecroed pieces. That keeps it tight against the strap and causes no sag. Sadly the eTrex had to go on my pfd, too bulky and it would be annoying in the even of a remount.