This is where digital can legitimately come to the rescue. If you don't have to hold an inventory of weekly comics, you just let your customers choose what they want to buy, and you make the same margin to sell them that you do on print, then you'd be in much better shape right?
Comixology's solution (as opposed to Diamond's which still required physical books to be purchased) is the step in the right direction we've been waiting for. You can sell and get paid without ever having to take a risk on holding inventory on those books.
I haven't seen the economics yet, and I know there is open question about handling sales in the App Store vs. sales on a DM's Comixology site directly. But I think it is vital that retailers try and band together to force the right solution onto the marketplace. I'm rooting for you.