If you can find a set of old school Onza brakes you can do it. They had a post that the brake pad moved on to adjust for wheel size.
You used to be able to get them on ebay, but I have not seen a set of them lately.
Here's a pair on ebay
http://cgi.ebay.com/Onza-H-O-Brakes-...QQcmdZViewItem
Last edited by Cyclist01012; 09-06-08 at 05:53 AM.
Reason: found link