I'm not quite sure what you mean by "pedal strap retention". Isn't that what toeclips do? They work just fine and hardly need to be reinvented.
Granted, I don't ride the track. I do make serious both climbs and descents on fix gears using equipment and technology that hasn't changed much over the past century. (I use modern shoes and aluminum slotted cleats set up for the three bolt LOOK pattern and Shimano 600 semi-platform pedals with their proprietary toeclips, but the end result isn't very different from the rattraps and nailed cleats before I was born.)
Ben