Eh, not really. You can download a windows pro ISO straight from microsoft [0], install it, and then upgrade it to enterprise using the kms client key [1]. That can then be activated using an open source kms server emulator [2] that has a reasonable amount of code you can audit if you're extremely paranoid.
If you don't want to go through the hassle of installing and then upgrading I'm also pretty sure you can upgrade one of the images in the wim offline using dism.
I do work on my windows machine, so doing anything illegal just gives me the opportunity to lose 1000x more money than if I just upgraded legally.