I would think a larger one would resist warping, but I could see splitting being more of a problem.
I ended up getting a cheapo set of bamboo boards from Bed Bath and Beyond last fall, lightweight, no warping yet, and if I get 5 years out of them it will be money well spent (it was probably $20 for a set of 3, plus keeping them conditioned will probably extend their lives).
I just went and looked at the reviews I had on a board (big honking teak model) saved on Amazon, CI recommended it. Terrible quality control apparently though, broken off the bat, cracks developing quickly, warping, etc etc.
I still need to buy a big carving board for the upcoming holidays, our big cutting boards were so leaky they prompted my purchases last year.