I do this, with my KPA lunchbox on top of the rack. Eventide H9 & Boss GP-10 on the drawer.
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I use sliding trays in my Samson rack that houses my "home entertainment system".
One tray for my mouse and mousepad that sits below a laptop which lives on top of the Samson rack, and another that houses a Bass PODxt for practice (that I've never used!). The audio interface that sends the TV, laptop and DVD-player audio to the speakers, along with a DVD player, sit between the two drawers in the rack. Works well. Neat and functional.
I bought the very best trays I could find, the Proel ADRK2PE model. Pricey, but I doubt you'll find anything that's better-made or more robust.
The Proel drawer looks great. My SKBs are heavy & take up too much vertical space. I don't see a US vendor that carries the Proels, though.
Yeah, I had to order mine through a "local" (interstate) store here in Oz and wait... It was worth it 'though.
They're the bee's knees, mate. So smooth, and so strong, which is why I said it's difficult to imagine any being better. You'll be amazed at their mass and level of refinement.
You're looking at a Merc, basically.
I use a drawer from Adam Hall (87556) but it is too heavy. My rack with the kemper and a power distributor, is a lot lighter when I remove the damned drawer.
Just saying to stay away from that kind of drawer! 
in the USA, here's one of the many choices http://www.parts-express.com/p…-w-fixing-points--262-280
