As far as I know Unicomp ( pckeyboards.stores.yahoo.net/adcolkey.html ) is one of the few or only makers of APL keyboards. They aren't bad and they're pretty cheap.
NARS2000 works about 80% with this keyboard. It would be nice if NARS2000 mapped this keyboard correctly (and without the Alt+ key combination requirements, i.e. naitively). Perhaps NARS200 could have a setting to use this mapping.
If this keyboard doesn't map correctly (and requires the special Alt+key combinations all over), what keyboard does NARS2000 support?