Prommys were made by a company called Nventiv that went out of business a couple months ago.
You might still be able to find places that have them in stock, but I have no idea what the deal is with their warrenty (I would guess they have none now)
Try a google search for vendors or the Mach I or II. I just tried for a second and couldn't find any, but you might have more luck.
You may be interested in a Vapochill. They are made by a comany called Asetek, and there are several models available. Some of them are small units that your case can sit on top of, and some of them are full cases with phase change built in.