Copy the Tyco "terrain Twister" screw drive?

I saw the Tyco "Terrain Twister"
http://www.tycorc.com/us/product.asp?category_type_id=22&id=11811&category_id=7819
advertised on TV and was intrigued by the drive mechanism.

It looks like it uses two counter-rotating screws/augers to move it
forward on bad surfaces like sand or snow.

I found a couple other references on the web:
The Ice Challenger: http://www.icechallenger.com/icechallenger/
SRL has one: http://www.srl.org/shows/phoenix/images/px29.html
and this halfbakery idea from 2002:
http://www.halfbakery.com/idea/Archimedes_20Screws_20Chariot_20Racers

Any thoughts on how this could be built as a robot drive base?

I've tried using flextube but haven't been able to duplicate this in Lego.

-Rob A>