Paramount 54"W x 42"D Flat File
Your review: File is cost-effective and functional. Outer steel skin is not strong enough to hold weight of drawers and inner frame during shipping, so despite elaborate and undamaged packaging, outer skin arrived noticeably buckled. Inner frame was intact, so drawers worked fine. I have ordered a counter top for my two stacked units from a kitchen supply company.
Pros: At around 250 pounds, this is probably a minimum weight and volume solution for a stack of 5 x 50" x 38 3/4" x 2" drawers (inside measurement). Drawers have 4 ball-bearing rollers each, and an anti paper curl design front and back. While not furniture grade, it's definitely a functional unit.
Cons: I don't see how this file could be shipped cosmetically intact without one of: a significantly stronger skin, an internal frame that doesn't rely on the skin for support, or shipping the drawers in a separate package. (I received two units with the same cosmetic problems.) There is already a lot of packaging material. No provision is made for bolting stacked units together - you have to drill your own holes.