Thanks! Although I haven't actually implemented the "default CNID backend for new installations" part quite yet — I wanted to move the config file to its new persistent location first.
If you use Homebrew, note that the netatalk Homebrew formula has been updated to include SQLite support. Also, its config file now resides in $(brew --prefix)/etc/netatalk/afp.conf (making it persist between upgrades) and the test suite utilities are now included.