The Atari crashed overnight, but I attribute this to two things: the kernel wasn't setting its allocation map to flag out $D000-$D7FF, and the prototype board is a bit flaky. Even the slightest brush against it might cause the system to go nuts.
Anyway, I fixed up the kernel this morning to block out the Atari's I/O range from possible allocation, and moved some code around, saving a few more pages in ROM which gave me room to stick mdir in the bootfile. Here's the result of that command:
It looks like we'll be going with a cheaper board making option for the first run, which will undoubtedly help bring the price down. No solder mask and no silk screen, just plain prototype boards. And we'll only make three instead of four. More news on that later.