The bookends aren't cheap at all. They aren't made of wood they're made of high grade/quality cardboard. They're extremely sturdy and well put together. The sackboy images on each are cardboard, but they're thick cardboard. The fact that these were made with cardboard was said within a day or two after the CE was announced. It makes sense why it's made of cardboard for a few reasons. Cheaper, weighs less (so shipping is less), and the world of LBP has that "put together with random normal objects" feel, heck the main character is a sack after all. Remember this CE is $20 more than the normal game, look at some other $80 CEs. Three that come to mind are Fable 3, TFU2, and Dead Rising 2.
The only cool part about Fable 3 CE was the big book it came in. It came with a decent metal coin and a deck of cards, and a minor pointless DLC location.
TFU2 came in a steelbook and a 2GB USB drive.
Dead Rising 2 is the best content wise of the three I mentioned, and it came in a steelbook with a pad of paper, crappy syrnige pen, folded up fake brochure (decent images, but it comes folded up so it looks crappy) and a bonus DVD (the only other good part).
The LBP2 CE comes with an actual plush sackboy (not amazing quality, but it is really nice), every single pre-order costume and then some, and the game/book ends.
What do you want for $20 more?