Installing a bigger hard drive in a stand-alone dvd recorder

Has anyone heard about installing a bigger hard drive into a stand alone dvd recorder? So instead of buying the $800 model with a 400 GB HD, just buy the 40 GB version and drop in whatever size you want?

I can't imagine these recorders are proprietary, but it's possible they're wired differently.

Any thoughts?

 

Might not be capable of holding such a large hard drive if it's a lot cheaper though.

 

Besides voiding the warranty, I've heard people upgrading their Hdd with the recorders. I think I read something about it on one of the audiophile sites. But, this was awhile ago. I have no clue exactly where it was.

What model/brand of device do you have?