I have a 72g bowfront reef-ready tank (set up as a freshwater currently), it's an Oceanic. LFS can usually order most tanks, but don't always keep all the options in stock. You can always ask what they can get. I think our LFS can get most tanks in within a week, depending on which day you order.
Personally, I'm not a big fan of bowfront tanks. They're hard to photograph, and not as easy to aquascape. They look nice in a room, but I don't think they're as practical as rectangular tanks.