We built one using the mechanism from Create-a-Bed, and it was easy, and quite nice when finished. It is the most comfortable bed we own! We put it in a guest room/study in our new house. The mechanism, plus clear, detailed instructions on building the bed, were included in the price. We paid $225 for a queen -size bed mechanism.that folds down from the side of the bed, so the longest part is next to the wall.
I found them at www.wallbed.com.
Address is: C.A.B.,Inc. 5100 Preston Highway Louisville, KY 40213
The order was shipped UPS, and shipping charges were included in the price.