I think the design is pretty top notch. The thing with their products is so much attention to detail is evident that you can see why it costs what it does. If you wanted to replicate it, you would easily be in it as much in your time cost.
I guess my only change would be the thickness of the velcro straps that you wrap around the bars that tighten up the canvas when it is deployed. I might also have boots built into the canvas flap used to cover the awning material when it is stored.. just to keep the ends of the "wall" zippers from flapping around. Not really a problem though, more aesthetic.
You would have to change the clamp that attaches to the Hannibal rack, but you would do that in your design anyways (assuming you aren't using a Hannibal rack?).
The biggest flaw with my setup (rtt, rack, awning) was the low quality fastener hardware shipped with the rack. That is an easy fix though.
About 6 years old and still bulletproof stuff, worth every dime.
I don't remember taking any detail shots, but you might start with this one that shows (a grainy) shot of it stored in the shop-
http://130.94.161.162/images/LC/ken/_MG_8246.jpg
this one isn't very detailed-