If my customer buys the decal and pays me to put the decals on the boards would that constitute an infringement on the college's trademark?
It's definitely trademark infringement, and no, you can't re-sell games that use other people's TMs. Do some research, even on this site, on pro and college teams. See how many AVVO posters are interested in trading illegally on these teams and league's trademark rights by using their TMs on various products. And no, it doesn't make a diference that the customer buys the decal and pays you to affix it to a game, it's TM infringement.
Avvo doesn't pay us for these responses, and I'm not your lawyer just because I answer this question or respond to any follow-up comments. If you want to hire me, please contact me. Otherwise, please don't expect a further response. We need an actual written agreement to form an attorney-client relationship. I'm only licensed in CA and you shouldn't rely on this answer, since each state has different laws, each situation is fact specific, and it's impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.
You want to use the decals with the logos because of the goodwill built with the public in association with the trademarks. That's precisely the reason that the owners protect the marks and why you cant use them.
The above is general legal and business analysis. It is not "legal advise" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.
You are trying to profit commercially by associating yourself with famous trademarks owned by others. Any time someone tries---without permission---to benefit commercially by an association with a famous celebrity, sports franchise, college, company and their intellectual property rights (trademarks, copyrights, rights of publicity), this person is violating various intellectual property rights and state common law rights. Instead of doing the hard work of creating an original game and marketing it to consumers on its own merits, you are trying to take the easy way out by piggybacking on the groundwork laid by others---their famous logos. This conduct is illegal--plain and simple. And if you engage in such conduct, you can expect a very expensive law suit--which will cost you a bundle of money to settle or defend.