I'm obviously very late in this discussion, but I have a couple of comments...
Many of the requirements requested could be satisfied with Adobe LiveCycle Policy Server. It has the ability to integrate with eCommerce, lock the PDF to a particular user so that it can't be freely distributed, and can allow the user to only print once (with a little bit of customization). What would be more difficult would be to allow the same document to change from a "purchased" format to an "unpurchased" format. I think the requirement could be better satisfied by just having them as two separate documents.
The comments about not responding to customer needs and not putting up R&D funding for this product are off base, in my opinion. I think we're simply talking about supply and demand here. There obviously aren't enough customers asking for this specific functionality, or else Adobe would likely already be investing in it. In my opinion, Adobe's willingness to build the product for a price is rather generous. I would imagine most software companies would not be willing to do this sort of thing. And to be honest, $25K is a relatively small investment to get your own Adobe-developed software product...I would think the price would be much higher.
Justin Klei
Cardinal Solutions