I assume this is for a gaming server and not a webhosting server. Otherwise, I could have helped for sure. I'll keep an eye open for sponsors out there, but usually they will want you to advertising for their company on websites/forums or forum signatures too. Mabye you should try a referal deal with a host. If you can refer them enough clients, they can probably give you a server for free and mabye some side advertising?

Good luck mate.