> And macports has binary distributions now so the awful rebuild-the-world updates aren't as much of a problem anymore
That's really awesome.
> ... has separate packages for every version of python so I can have them all installed at once for testing
Are the package versions themselves configured to be installed side by side? Or are you using multiple copies of macports[1]?
[1] https://guide.macports.org/#installing.macports.source.multi...