Update!
I've made the necessary stand modifications by taking off the "back" of the stand (it will be just one of the long viewing sides for me) as well as the shelf and the back mid-span post. Turns out none of them were load-bearing and were mostly held on by long wood staples. A hammer and a screwdriver used chisel-style disassembled everything pretty easily. Eventually I'll put the back panel back on (loosely).
I've acquired a 20G sump tank and a Quiet One 2200 pump for the return, I'm estimating 350-400gph after head loss, a little less than originally planned but still more than enough. (thanks kissel!)
I've ordered 25lb. of dry Fiji MarcoRocks plus 20lb. of dry shelf rock that will arrive tomorrow. I probably will end up with a few unused pieces, I'll just put them in the sump for the time being (on a shelf above the bottom to prevent trapping detritus.)
So, once the rocks arrive I will begin the real task of aquascaping. Since they're dry I can take as much time as I want and really play with different options, I'm going to borrow a drill so that I can drill holes for both the posts (plastic coathanger pieces, 5/16" and 1/2" diameters) and frag plugs.
Here's my next question, I'm not sure if anyone here as experience with this. I'm going to go with a barebottom system, which entails limiting as much as possible the areas around the bottoms of rocks that could trap detritus (good flow around the bottoms of the rocks). The three methods I've seen are 1) glue the bottom of your post(s) to a clear acrylic base about the same size as the bottom of the bottom rock which will sit directly on the glass, 2) mount the bottom rock on short (~1") lengths of PVC or 3) just put the rocks on the glass and arrange them to minimize dead spots. The bottom glass is tempered, so it should be fairly strong, but I want to avoid point stresses where lots of weight is on a few small spots. The acrylic base would probably be best for this and is where I'm leaning at the moment. Any ideas? Without seeing the rock I'm not sure which of these options I prefer. Over the weekend I'll have some time to play and I'll try to post pictures. I also need to find a perfectly level piece of floor before I put in water.
Also, due to the arrangement of the tank and stand I have one additional unusual feature to play with. If the tank is bare bottom, there is no visual obstruction between the display tank and the stand/sump. Anyone with ideas for neat visual tricks I could play with this aspect? I was thinking maybe mounting LED's underneath the bottom glass for spotlighting specific corals/ other elements. Or I could just mount a mirror for maximizing light. In either case I can actually keep the bottom panel clean of coralline with a magfloat.