In the end, it's all market-driven business. Factories don't make thousands of anything on speculation. Wholesalers who order the stuff don't take too many risks or they won't be in business too long.
Ukuleles: Martin T1K (T), Oscar Schmidt OU28T (T8), Lanikai LU-6 (T6), RISA Solid (C), Effin UkeStart (C)
Banjo-Ukes: The Duke (T), Lanikai LB6-S (S)
Tenor Guitars: Martin 515, Blueridge BR-40T
Tenor Banjo: Deering Goodtime 17-Fret
Mandolin: Burgess (#7)
The inventory is always in some flux, but that's part of the fun.