Home prices are falling, but haven't they been building bigger houses lately?

Saw an article claiming home prices still had a long way to fall based on the ratios of price-to-rent and price-to-income compared to their historical averages.

What I think is interesting is that in my area home builders have been building larger homes in recent (~10) years. There's research out there to support the idea that people spend as much money on houses as banks are willing to lend. And, around here at least, as banks became willing to lend more, the home builders accommodated them by offering homes that cost more to build. (There's lots of land here, so there's no supply problem like on the coasts.)

That implies that if the price-to-income ratio falls, these recently built homes will be bargains selling for much, much less than their original cost to build. Probably won't fall beyond the scrap value of the fancy copper roofs, though.