I've seen some of these too on E-bay in the $800.00 price range. SpoonMan may know off the top of his head what the warranty is on Def tech Super Cubes since his got a I and looking to go for a Reference soon.

It's always nice having the piece of mind of the factory warranty but then again its likely only good for less than 5 years and from what I can see the build quality on these things is excellent.

I'm also looking at the SVS CS-Ultra Subs as a possible choice too ($1299). The guys @ SVS are so good about answering questions specific to your HT setup and room. I've narrowed doen to either a SuperCube or an SVS CS-Ultra.