Actually, it appears that the kernel I built from the 4/28 snapshot
didn't work because I was using the linker in src/gnu/dist (rather
than toolchain), which is buggy.  I'll work on this.

The 5/1 kernel uploaded by Tsubai, and a kernel I built on the Mac
itself with the tools from February, both work fine.  Indeed, my
previous problem of random network-related crashes is gone!  This
kernel seems to work really well (except for not supporting the video
card in the 7300/200 yet).

I think the port should be committed to the CVS repository.  B-)