Surely there's some way for valve ot make money off this. What if you signed away all promises of suing and let them sell it on the steam store for a small price? Just having it on the store would open up tons of potential payers.
Look at this entry on Wikipedia.
http://en.wikipedia.org/wiki/Modding#Game_software
There are no official laws on mods as far as I know. CS was acquired though, why not let Valve acquire FF?
If you "interfered with their business model" then offer them a better business model. Allow them to make money here somehow. I mean, you're going to make 0 dollars off this anyways, right devs?
If it got mentioned in a TF2 blog post just once, it could get purchased, since the market for games like FF is in TF2.