Hey Richard, that looks awesome! When I converted my 100gal and 55gal from Cichlid(all Malawi from Gabe's Fish), I donated my holey rock to an upcoming enthusiast. Out of curiosity, you have anymore live rock in the back yard you may be willing to part with or sell? You seem to have some pretty nice pieces size wise.
I'm picking up a 75gal from a guy on this site when he gets it empty and it will be joing my front room with the two SW setups. This one has the overflow too, what filtration are you using, or have a pic of the plumbing? Can't wait to get my cichlids back again. I think I'll be sticking with Malawi again. I like the black sand idea, I had limestone in my last one(black and white). You going to possibly put any sword plants in with those guys? I had good luck with growing those in mine.....