My collection includes some very rare models, like a pre-series macintosh portable, which was not for sale or the powerbook 2400c, which was produced only in small series for the japanese market or the very fast powerbook 3500 (G3 kanga). I own also a PPC-upgraded powerbook 540c or a G3 333GHz processor upgraded powerbook 1400c or a G4 500MHz upgraded powerbook wallstreet.
And fortunately I got also the rarest powerbook: The amazing powerbook 550c from the 500 series, which was built in 1995 - only for the japanese market. The powerbook 550c came not in gray color like the other 500 series, it was actually the first powerbook in black.
I'm always searching:
1. powerbook 550c (found it in cosenza, italy)
2. powerrbook 2400c (found it in la, california)
3. powerbook duo 250 (found it in berlin, germany)
4. powerbook 160 (found it in zurich, switzerland)
5. powerbook 145 (not 145B) (found it in varese, italy)
7. powerbook 1400c 166 (found it in magdeburg, germany)