I saw somewhere out on the web a home shim job that involved gluing pencil erasers (cut off the ends of pencils) into the brake levers. I think it might have been on Sheldon Brown's web site? So I'd say yes it can be done.

On another note, I was hanging around in a LBS the other day and they has some SRAM outfitted bikes next to some Shimano short reach outfitted bikes and I had my own bike with DA levers. To tell the truth I couldn't feel a whole lot of difference between any of them. I think I might have been able to get my pinky finger onto the short reach ones, but I don't brake with my pinky so it didn't seem like too much of an advantage. I did notice that the SRAM levers were quite a bit shorter (top to bottom of the metal lever part), which I thought might have actually made them a bit harder to get all my fingers around them.