Sorry no special source. I made it from scraps around my shop. The drawer is the small plastic tool drawer from an old Kobalt tool box I got from Lowes. Then I attached some 1"x1" aluminum angle stock to the drawer with pop rivets. The glider blocks on each side were just made from wood scraps and attached to underside of cabinet with appropriate length screws.
There is a product available at CampingWorld that I considered before I decided to make my own.
Hope this is helpful,
- - Mike
2013 Lounge EXT on 2012 Sprinter