If you are interested in optimum keyboard ergnometics, I highly
recommend the humanscale keyboard arm. Its got a combined height and
tilt mechanism that is adjusted by simply grabbing the keyboard and
moving it. The whole thing slides up under the desk to completely
disappear. My wife and I share a desk. She is 5'1" and I am 5'11".
This arm allows us to set the keyboard for our own fit without having
to mess with a bunch of screw type locking mechnisms.
The ergonmetics is far superior to any kind of sliding drawer mechanism
and helps with preventing carpal tunnel syndrome. It bolts under any
desktop with six screws.