it's like this one on eBay which is two models ago.
http://search.ebay.com/rainbow-vacuum-cleaner_W0QQfsooZ1QQfsopZ1QQssPageNameZWLRS
here's a nice one
http://cgi.ebay.com/RAINBOW-SE-D4C-W-POWER-STAIR-HEAD-AQUA-MATE_W0QQitemZ4462676674QQcategoryZ43520QQrdZ1QQcmdZViewItemedit to add, if you do buy one, three things to make it last forever
NEVER NEVER let it sit on the pan of water. if you can't dump the water right away, at least take the motor OFF the water pan. even a few hours will start to damage the motor
#2 when you first get it, it will pull the dust all the way out from the carpet pad and it will turn the water to mud for the first few times you use it as you get the years and years of dirt out of the carpet and from under the pad. check your water frequently to insure it's still liquid. change the water often the first few times you use it. you'll know you're good when the water is just cloudy instead of black and there isn't any "sludge" when you dump the water pan.
#3 clean the "separator" regularly. check it every time and clean it when the fins get dirty
let me know if you do get one, DH sold them and is great at how to care for them. the tips I gave you will give you years and years of service and help with any allergies like you wouldn't believe!