Having worked for a university, I can tell you that unauthorized use of a copyrighted college logo or mascot image will likely result in legal action against the person using it. This includes images that look similar enough to the copyrighted image that they could be mistaken for one another. The big schools make a lot of money selling items with their logo or mascot, and they do not like it when someone else tries to cash in on it.
For example, there was a case of a high school in another state using a mascot image that looked very similar to our university mascot. They were notified by the university's lawyers that if they did not stop using it, they would be sued for copyright infringement.
Knowing that, my guess is that unless the university has granted the use of its image on an "official" authorized rubber stamp, you will not find one. And if you were to create your own image that looked close enough to the original to be mistaken for it, and then used that image to create items that you were selling, you would likely face legal action for doing so.
I don't think you're likely to find a rubber stamp of a collage mascot, because it wouldn't be a big seller. But most schools have stickers, transparencies, fabric or embroidered images, etc. You could use those items on a card without incurring the wrath of the school (but they're not always cheap! You can find items on sale, but it's usually during the summer when they're trying to get rid of "last year's" designs to make room for the new stock.).
I would start by calling the school's on-campus bookstore to see what they have. You could also check with local stores in the area that sell the university's clothing and other items.
Hope that helps.
Grand Goddess of GPS of America - BCBW Chapter
Last edited by missiowa81; 10-01-2012 at 10:47 PM..