Actually all mad dog enclosures half price at compusa, the 5.25 and 3.5 usb seem to have cypress chipsets, the 3.5 usb/firewire seems to be initio.
Here is a litle more info.
Online they only show one on sale but the print ad says all mad dog external enclosures half price (in store only probably). You may have to show them the ad and point out that they are all suposed to be half price to get the price on some but they usally don’t give you a hard time about it (same thing has happend with mad dog fans and ide cables when compusa had all on sale half price).
My other post about it
Fat wallet thread from when they were on sale two weeks ago that discusses them (what chipsets etc).