You can probably do anything python-related from any of the distros you mention, but large parts of Gentoo's infrastructure (including Portage) is built in python, and it contains good tools to, for example, switch the system python interpreter between 2 and 3 series and automatically rebuild python extensions that break when you update python.
Gentoo also has good support for installing many versions of python at the sam time, currently 2.4, 2.5, 2.6, 2.7, 3.1 and 3.2 are available (and presumably maintained) in the official tree (3.2 marked as unstable).
Also, apart from Fedora and Gentoo, all of the mentioned distros ship pretty outdated python versions afaik. (In fact they ship outdated everything.) That might be what you want, or it might not.
Edit: If you want to keep a separate, user-built python install, the choice of distro makes no great difference. Pick the one you like. Gentoo is simple to install wihtout X, so if you only want command line or ssh access in a VM, you'd save a bit of downloading and disk space.