Hey Rob,
I understand that you went with Aspen because it was light, and you created that inset piece to give it a wider surface to run on (To protect its life).... However, just curious... Why not just rip an 1/8" or even a 1/4" off the bottom of each drawer side, and then glue up a piece of hard maple to take the place of the piece you cut off? Seems like that would be a lot less work, and a cleaner design on the inside of the drawer? I get that it won't be as wide (the bottom of each drawer slide), but heck, I don't think you will wear out the hard maple.
-Joseph