I was thinking of that myself a while ago (couple of weeks)
there are some good sites that you can design them on...
like
http://www.spreadshirt.net/shop.php?sid=44009oh white would be good, or a light pastel colour for the t-shirt.
if you went for a dark colour you would need a light logo, as I dont think that BallReviews would like you 1st using the logo and secondly changing the logo.
and you could have 'Grip It and Rip It' on the back, that would work....
or even , Grip It and Rip It on the front and the logo on the back.
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MonkeyBoy