Ray,
I was successful in building and booting my ZFS based system mostly following the guide, however I deviated in several important ways, including building a mirrored vdev and installing grub to both bootsectors to allow boot if one has failed, updating the kernel sources before building spl and the zfs userspace & modules, and most importantly, modified the grub configuration to autodetect and look for the right filename for my kernel; also, I don't have swap on the pool.
I am going to do a reinstall on my machine this weekend, not including recreating the datasets, and I will further evaluate the guide, the zfs packaging, and genkernel itself for issues which may need to be fixed or clarified.
Take care,
~~~Chris~~~