the deep blue stand is really nice, but has a big downside. its built well and very stylish if you dont want the common pine wood stand. i was very happy with it...except the front brace. if you look at the stand, the carbon fiber front brace covers almost half the front of the tank. its a pain to work around. i highly reccomend getting a custom sump. customking (jeff) custom built me an amazing sump.
sadly, this whole set up was sold a week ago and do not have it anymore to tell you for sure, but in dont think 12" wide will fit. there is a side door on the right side of the stand, and 12" would fit, but there are 2 extra support beams in the back of the stand and its a real tight fit. when i had my sump made, i had it made 11 inches wide to be safe. i also built a cool roller device with a slide out tray, so if i ever wanted to do serious work down there, i can just slide my sump out.
hope this helps