One of my beefs with keyboard drawers is that the keyboard usually ends up being at the wrong height for me. I found a height-adjustable drawer while browsing at Amazon though (3M Adjustable Keyboard Drawer). Since Amazon didn't have a picture, I hit the 3M product catalogue and found some more information. It looks like the keyboard trays come out from a metal monitor stand, at least from the pictures.
It wasn't clear from the product description whether it just sits on the desk or holes need to be drilled (I'd be more likely to drill a hole into the bottom of my desk than the top). Has anyone used one of these adjustable drawers? If so, do you like it? I'm still looking for something to hook up to my desk. Right now, I tend to just put the keyboard in my lap to type.