You must find someone that has full access to big signatures and some authority. If I was to do this I would contact a member that has Hero status and above and go from there. Basically you need to start a signature campaign thread, and you will need a escrow to manage your funds to make people trust you in your payments.
you say that is better paying to users to put my site in their signatures ?
Depends on budget and who you are able to get to wear signature. If you get some solid users who are not spamming for money... you can do a good signature campaign. But does take time to run it, do payouts, most likely you would need a esrow at least at start. But lot of time put into this, and I think getting good members for it is key.
If you have a higher budget you can bid on ad's but it is going to be pricey as MANY sites want these signatures. The forum is worth a lot on ad space. And it will always be biding as it get's the most money for forum. Also one who wants worst (ie high bidder) get's it.
So all kinda depends on your budget I think.
