Michel,
I know Tracy has mentioned this to you already, but I'd also like to suggest it too. Would you consider un-merging Kevin's account from Grover's? You can keep the ban (on both of them), but I worry that if Kevin really isn't Grover (and he strongly insists that he isn't), then it would really suck to have all those really bad posts by Grover be attributed to someone (Kevin) who really never said that.
OK, I know that you believe that Kevin really is Grover ... but what if you're wrong?
~~Bonnie