No, but you can create other bookshelves, and they will hold PDF's as easily as other books.
When you are looking at the bookshelf, you should see a Collections button right next to the Store button. If you tap that you'll see your two default collections; Books and PDF's.
At the bottom of the list you'll see a New and Edit button. To make a new collection (bookshelf) tap it and give it a name. To delete or rearrange the list tap Edit. You delete a collection by tapping the minus sign. You can rearrange them by dragging the three lines to the right of the name.
To move books into a collection go to the bookshelf you want to move the book(s) from. Tap on the Edit button at the top right of the bookshelf, then tap once each book you want to move. The selected books will show a blue checkmark. Tap again to deselect if you made a mistake.
Now chose the Move button at the top left. You'll see your list of bookshelves. Just tap on the one you want to move the books too.
Tap the Done button at the top right when you are done editing.
This all works pretty well. My only complaint is I would like an All Books shelf that always shows all your books, no matter where you move them. Unfortunately, if you don't remember where you put a book, you'll have to manually search all your shelves.