I couldn't find anything I could afford that was to my liking. Also, the room I work in (built into half of my 2-car garage) is pretty small. I decided that built in counters and shelving was the only way to get any efficient use out of my limited space. There is a picture of my setup on my website. The picture shows the keyboard/mouse on the countertop. I found this to be uncomfortable after a while. I bought a $10 plastic keyboard drawer for the drawer rail hardware, through away the plastic tray, and made a tray out of wood that is wide enough for the keyboard and a mousepad. This is hung under the countertop and drops the keyboard & mouse down so they are almost in my lap as I sit in my chair. Also give me some more distance from monitors. It also slides out of sight under the counter when I'm moving around dubbing or whatever. It's a nice set up
I built my counters out of particle board (for the tops) and plywood (for front edges and bracing underneath) and covered with formica. I like it, but it took an awful lot of time to build.
Here's the URL for the large size picture of my edit room showing the counters/shelves: