Managed to find an image of the 2001 Gatchaman one-shot by Kazuhiro Kumagai (Samurai Gun), and it says right on the cover that it's only 33 pages long.
Considering how few Gatchaman manga there are I imagine that's why it's never been reprinted. Licensed IP manga can be a pain to deal with.
George J. Horvath
The only Gatchaman mangas I know of were either manga-style adaptations of episodes that ran in magazines(so not really Gatchaman manga) and an extremely unpopular Young Jump one-shot by Kazuhiro Kumagai from 2001, one so unpopular that it never got reprinted, not officially.
