I had the clear back shell from joy factory on my ipad2, but after a while dust and debris got under it and made it a necessity to take it off and clean it frequently. Eventually I got fed up and bought a leather folio case instead.
That's exactly why I want a back cover WITHOUT Smart Cover integration.
For those of us who aren't worried about Gorilla Glass scratching but are worried about the aluminum scratching, there simply aren't any TPU or plastic back shells that don't have the whole left side exposed like an open wound.
The only one I've seen so far without Smart Cover consideration is the SwitchEasy Nude and it isn't certain that they'll be making it for the The New iPad.
Article describing the Switch Easy Nude here:
http://www.gadgetmac.com/gadgetmac/2011/6/23/switcheasy-coverbuddy-nude-cases-for-ipad-2-review.html
BJ