Can you use a wireless external hard drive as a time capsule?

Hi guys
I've seen a few external hard drives that are now packing wireless so that you can wirelessly stream your data, similar to a time capsule. I really time the idea of the time machine etc and i want to use the feature on my new macbook (which i LOVE!) but i don't feel like spending a bucket load on a time capsule if i can just get a wireless hard drive enclosure and use it as a time capsule. Does anyone know if this would work?

If the hard drive is OS X compatible and can be mounted (shows up in Finder and you can read and write to it) then you SHOULD be able to use Time Machine with it...

That being said, save your receipt just in case...