Now that I think about it more, a good person to check with would be Mr Mint who's a big sports memorabilia collector.
His site is at http://www.mrmint.com/
and he goes from show to show buying memorabilia. One of the recurring segments on WGN Radio during the morning show is him calling in and providing phone valuations of the callers items. You can contact him by clicking on the "Ask Mr Mint" link.