Spent the past couple of hours doing the usual weekly backups (photo archiving, laptop snapshots, etc.) and fighting the peculiarities of the aged Linux box I use as interim storage. Turns out that the kernel on that machine will pack up with long file transfers when the filesystem is not yet noticeably full (at least from my standpoint), so while trying to figure out why the backup was so damn slow I was getting ping times of 100s (!) on the LAN.
Guess it's time to get rid of all that crappy Intel hardware... Er, no, wait...
Update: In the meantime, Mac OS X C developers may want to give pfig a hand. My cursory investigations into the BSD innards of Tiger led to pretty much the same dead end, but someone out there might know the answer...