I like the mid-evilness of the ones with the bat, but I am not a fan of the bat itself. I would also like to see the incorpration of the motocross bike into it somehow...
I like your entry # 59 but the scale of the person with respect to the bike doesn't look right or the bike looks too heavy. # 61 I would have the same comment, and in addition I don't care for the jagged roost off the back tire, maybe it could be more literal and look like dirt chunks flying off...