At the moment I'm building a cross toolchain (i686 to x86_64) so I can build a x86_64 flavor of the awesome linux_kernel-2.6.32-42-lts.
I want to build a 32-bit Puppy with a 64-bit kernel, that's what the Tiny Core guys do and it works well for them - you get 64-bit math, 64-bit drivers, support for more than 4 GB of memory, and all this goodness without sacrificing compatibility.
Another interesting thing about this trick is the ability to run 64-bit stuff. Just think of it - you build a Debian chroot environment with debootstrap, which contains Debian's 64-bit GCC, then build all Puppy's 32-bit only packages for 64 and gain the ability to build an entirely 64-bit Puppy
![Very Happy :D](./images/smilies/icon_biggrin.gif)