This was a recent thread I participated in: https://discussions.apple.com/message/15334501#15334501
I believe the answer is no but hopefully you either read some of the other discussions or contacted iTunes support and they were able to provide a good solution for you.
Sorry you did not get a more timely response from the user boards.
In iTunes (in your PC or Mac) go to the home page of the iTunes Store. There you have a link to your purchase history. In that page you can select the Books page and manualy hide that item from the purchase history.
PS: that only works on the iTunes you use, at the iPhone ou iPad it still shows in the Purchased list of the iBook application