It seems too high to me. There's a guy here on MFK who has a cousin who makes brand new acrylic tanks and he was selling a new acrylic 300 for $1000 I think. It's got the overflows too and he said he could ship it. Forgot who it was but just do a search for "300 acrylic" in the for sale threads. You have to buy the stand separately, but you can have a good one made for just a few hundred bucks. The filtration, live rock and live sand you can probably buy at a big discount from someone on CraigsList.
I agree with the other people who said go with acrylic instead of glass. For super huge tanks above 200 gallons, the weight of the water is going to put a lot of pressure on the seals of a glass tank. Also, a glass tank that size has to weigh at least 600 lbs. You'd need to have a few big guys help you or hire movers to do it and they'd charge you an extra $150 at least. When I bought my 210g tank and stand from CraigsList, i was able to move it with the help of just 1 friend.
