Doug,
Glass Cages worked for me due to the availability for pick up vs shipping and it's related cost. Granted there is a pick up fee, it's equivalent I guess to paying sales tax if I bought it locally. I'm also not sure of their quality but no local (only one that I know of and had done business with years ago) tank builders offer starphire glass and the tank I had them build me 15 yrs ago (they build tanks for the Brooklyn aquarium) used regular glass, was euro-braced but they still needed a glass center brace, glass pane joints were not perfectly even, unscored silicone edges and all this on a 90g tank that cost more than a standard 120g euro-braced tank from Glass Cages.
If I was willing to pay the cost of shipping (which would probably equate to 90% of the cost of a tank), I would pick Inter-American up in Canada. I've seen one or two of their tanks and the little touches such as black silicone with scored edges and perfectly flush glass joints tells me that the quality is there.
Your right on the dollar mark for the $580 amount. I also ordered the oak stand and canopy since I have the carpentry skills of Homer Simpson. So $280 for the 30" stand and $140 for a 12" canopy puts my total at an even grand plus $80 for the pick up fee.
Pick up of the tank would be next Sat or Sun, I'll probably shoot up there with a friend on Sunday.
What was interesting and a bit of a shock was when I called them back yesterday about 5 hrs after I ordered the tank to check the placement of the overflow holes and he told me that the holes were probably drilled and that the tank was most likely assembled already. I originally asked for a 10x6.5 overflow box with two 1.5" drains drilled on the bottom. When I called him back to make sure the holes were placed in a way so that I can install two Durso standpipes, he told me that he would have to widen the box to 14" whether the holes were drilled already or not. He said I needed the additional length if I plan to install dual Durso standpipes. Hope this helps in your planning.
I also did not ask him to drill any holes in the euro-brace due to him informing me that if I wanted 1.5" holes in the euro-brace, he would need to widen the euro-brace to 6", which I thought was a bit much for the perimeter of a 48x24 tank. I figure it also wasn't cost effective (yeah right, the guy who bought a $40 acrylic backer cause he was too lazy to paint the glass) for the added charge of the extended euro-brace and $20 for each hole I wanted which would have been 2 for the 3/4" Sea-Swirls and four for the 1" OM 4-way returns.
For now, I'll just purchase the acrylic tank mount adaptors for the Sea-Swirls for $19 a piece and mount the overhead PVC returns for the OM 4-way similiar to what 5y5tem Overload is doing in his setup but just with the back returns hugging the edges of the center overflow so that I can get my Sea-Swirls in the back corner.
I'm going to shoot for two Reeflo Darts, one to run the OM 4-way (thanks for the idea!

) and the other from the sump return to be tee'd to the pair of 3/4" Sea-Swirls, an EV-120 (I know I need to upgrade this, but I just have this sitting in a box), feed for Ca reactor, feed for Phosban reactor and somewhere in the this mix, I need to plumb in my chiller.