Thanks Aaron and Bill. It's a good point about the cost of adhesive, especially since it will take a lot, gluing the faces together. Is thickened epoxy the best choice? As Bill said, I have the wood.... As to clamping, I'm thinking of stacking them and using weight - probably cement blocks on a timber (the strong back?) to spread out the pressure.
Will

: Laminating them that way wouldn't have any effect on the bending, or
: shouldn't anyway. Might be a trick getting them clamped but otherwise no
: problem. Heck, you've already got the wood, might as well use it and the
: clapboards usually are clear and straight grain too

: Bill H.