That's great if you have control of your server.  If you are using a shared hosting partner, maybe they would do this.  Of course, they would have to do it for each site for each of their customers.

Although it was a bit painful, updating all of our skins worked and we actually generated new business by going back to the customers and proposing a redesign where we charged them a small re-design fee.  A couple didn't want to and those were the 3-4 sites we had to 'fix' the old SolPart skins.