Interesting idea, Lee. Probably a little complicated to add at the last minute, but we may look into getting a few books graded and making them available after the book comes in. Thanks for the sugg!
How about adding a 'graded tier' where you send in a copy and have it professionally graded? All backers at the graded level could be sent in at the same time and the first backer would get the best graded and so on. You could even have a graded+signed/verified level for those who want sigs.
My ideal tier would be a super high rez digital copy and a signed CGC 10.0 to hang on the wall...;)