RFC: Location for Device Tree Sources?

Folks,

Where should we place the sources for the OF Flat Device
Tree source files?  They used to be in U-Boot, but that
isn't happening any more.

One semi-obvious place would be to co-locate them with
their corresponding Linux arch/powerpc/platform directory.
Another would be to have a new directory full of them
under, say, arch/powerpc/devtrees or so.

Are there other suggestions or better ideas?

Thanks,
jdl