I can sell you the "Lazy Reefmeister" Sump for a mere $300 firm!
Its a 55 gallon (48x15x16) acrylic sump with triple baffles at each end creating the exact same configuration you have shown above. It also has a 7" filter sock bracket and 3-probe holder mounted in the skimmer compartment....this is a Plug-n-Play sump!
I ran over 2,000 GPH through this sump with not a single air bubble making it back to the main display tank....VERY well designed
You can see it in action here in my thread on RC:
http://reefcentral.com/forums/showthread.php?s=&threadid=579223
Comes with all 3 sump-section valves, the main dump valve, custom PVC manifold, and unions (over $150 worth of plumbing parts alone) but NO pumps.
$300 firm, pickup in Garden Grove
Kevin