Comment by nwallin

That wouldn't work either.

It would heavily favor distros that require major upgrades every six months or whatever over rolling release distros.

With Gentoo, the ISO doesn't matter. You can use any bootable linux distro. I generally used knoppix back in the day, these days I generally use systemrescuecd. I installed Gentoo using the Ubuntu installation disk once because it was the first bootable linux disk I saw. I've used Gentoo as my primary OS for almost two decades and I've only ever downloaded an ISO maybe 5 times.