Membership automation options?

Here's my scenario. I'm offering an ebook for sale and I want to use Membership plugin to create an area where the customer can go to download the book. This means that when they purchase the book they're really just purchasing a subscription to get access to the book.

However, I don't like how a user needs to register an account BEFORE they're given the option of purchasing. I feel this will distract some users from going through with the purchase. Is there a way to have the registration occur AFTER the purchase? Or at the very least have it occur on the same screen as the purchase (basically have the register and subscribe happen on the same screen)?