A couple years back I did several owl shaped mini book classes using an owl book base from Best Creation. I was told it was discontinued but I found some!!! I chatted on the phone with the Frantic Stamper yesterday and she just so happens to have some of these fabulous books in stock.
If you have ever purchased a pdf from me for an owl book (or plan to now) then here is the link to get the base so you don't have to hand-cut it:
Scroll down to the Owl book on the lower right of the page. You will have to call them to put in your order but they are very nice and answered the phone promptly.
Also, I just listed some Tree Shaped Books from Maya Road for the "A Little Bird's Tale" Mini Book PDF I have for sale as well.