I've discovered something amazing!  Apart from developing carpal tunnel and horrible vision from many hours of using a mouse and keyboard, I have developed keyboard callus.  Exhibit one: Korean Starcraft Players.

Totally not being stereotypical... not all Koreans play Starcraft.  Probably.

It's more like mouse hand, since it's only on the right, and when playing games my fingers are only on the WASD keys (pretty much my default position)  my left wrist pretty much never touches the desk. Here's a picture of my very obvious callus:
Compared to my left hand:

Notice the very prominent veins.  The people at the blood center love me.  I could probably be a very good druggie.

Sadly, I could not figure out a way to compare them side to side because well... taking a picture of my right hand was hard enough.  Taking a picture with no hands is a no go. 

I can probably guess you are confirming your own right now.  Yes, your wrist has grown extra padding to accommodate for it setting against a hard surface all day.  I wouldn't be surprised if my wrist bone has grown as well.