how about DC++?
 

i use DC++ (Direct Connect PLus Plus) a lot and i think it would be a great idea to keep GCW alive. all you need is a hub and an operator (or bot) and the software to setup the hub. all info can be found here: Dc++ and the hub setup guide can be found here: Hub Setup.
dc++ really depends on the amount of users but it is a good way of helping GCW stay alive and free. :D

paying for one crack or lifetime membership!!!
 

I would suggest to let the people pay for each crack they download and I would reduce the amount of cracks you can possibly download. Paying could be made with some own gcw dollars as a currency. And I think that there is too small disclaimer that tells you to click a banner. Why do the people get their cracks before they clicked a banner? Why is it so? If nothing helps the membership is the greatest idea I ever heard of. The people are possibly addicted to the cracks, they would pay a fee for one year or a lifetime membership in every case. This is just a ill-minded opinion of a registered user.

A bittorent inspired P2P system is on its way, called eXeem.
A news report can be found at here [anime-source.com] and here [slashdot.org].

Perhaps it would be an idea to see how this takes off before implementing your solution.
Edit: Added slashdot news link.