So there's this maniac thund3r on #NetBSD, who's working on
porting the Gentoo "portage" system towards NetBSD. For everyone
interested in his work,
check out his weblog!
I admit I haven't found time to look into this in-depth, but he
seems to start with pkgsrc-installed things like Python, which portage
uses, and then bootstraps things.
See the install