The forces exerted on a hanging load like this pose an incredible challenge on both the hardware as well as the fasteners.

Speaking from experience, I once built something similar using two heavy-duty full extension drawer slides mounted to the underside of a desk. As long the load was simply suspended it was relatively solid, but after only a few months of regular use the ball bearings started to fail.

The challenge is the force of gravity acting on the slides which are designed to be used in a vertical orientation. Those forces are compounded when the hardware is open and rotational forces also apply.

Is this going into a cabinet, have you considered using traditional hardware but mounted against the top of the carcass, with your "drawer" hanging from it? (Similar in concept to the pantry slides someone recommended)