I actually did look at custom pricing. Even with shipping and low iron glass it's $100 cheaper for a 48x24x24 and $200 for a 48x20x20. It's not so much the tank price that has me scratching my head, it's the flat $300 shipping they are charging. I rant it thru my shipping quotes and the most expensive I got was $78.For a rimless 80G tank, I think that price is similar to other vendors like a custom tank maker. Depending on the dimensions, it might be cheaper.
Of course, you'll pay shipping they'll bump up the price.
Me, none, but I saw 1st hand tanks they have shipped and I can't tell you how many bad reviews on reef central. Granted this was all 7 ish years ago, but as some one that did work for a custom tank builder I was shocked.
it's part of a much larger remodel. Having the ability to run water power and sewer to its location is what makes it interesting. I honestly think it's a bad idea, for any number of reasons, but hey, if I get too build a tank on some one else's dime...If the dentist would sign a waiver saying you're not liable, you can start building. There are ways to get around legal issues.
Of course test the build for quality first.