You'll not find an end-to-end open source solution, the internals of fpgas are closely guarded secrets and there isn't really any way to get to a bit file without using the Xilinx tools
They want a valid address for the license to cover their ass, I have one with my home address and one with my home address
It may say something like you can only move a license 5 times and to make sure you have stopped using the old host, but I've never had any problems, just generate a new webpack license for the new host
I believe you could also use a virtual network card
-Lasse