A rigid fork (i.e. no suspension) but taller than regular rigid forks, so that it fits on bikes that were designed for suspension without lowering the front. Here's an example:

http://www.jensonusa.com/store/produ...+1X1+Fork.aspx

What size of bumps are you running across on road that are hurting your wrists? That is usually more related to fit problems -- too much distance from seat to bars making you lean forward and rest too much weight on hands, for example, or using handlebars that put your hands at a strained angle. I can't get along with flat handlebars personally.

http://www.sheldonbrown.com/pain.html#wrists