Yes, I looked at Puget Systems stuff briefly however at those prices the idea was quickly dismissed... plus I'm not too keen on the whole rounded look that the aquariums give the system.
Unfortunately your only other alternative is to buy or build your own 'aquarium'.
Also, you can't forget the cost of the oil, at $15 a gallon (I was only able to find mine for $17...) times however large the tank is... looks like 12 gallons minus whatever is displaced by components, likely to be about 10 gallons in the end. That's another $150 (at least).
So you are now up to $750.
If you go the 'build your own' route, like I did, things are much much easier on the wallet.
I'm going to estimate I've put $400 into my case so far, shown below...
($125 for acrylic, $100 for pump, $75 for oil, $100 for radiators/fittings/tubing)

Drying by the fireplace after washing it off
Now, obviously if you want to make a bigger case gotta throw more $$ for acrylic and oil (mine only holds ~3 gallons of oil and mATX motherboards)
The do it yourself way takes a lot of time, but I've had tons of fun with mine so I can't not recommend it
Edited by RedShades - 11/30/11 at 3:36pm