Pull out shelf in cabinet?

[lost in space]

When I built my main workbench, I used drawer slides rated at 100 lbs. They've been great for six years now, knock on, well . . . . wood! Sides just tall enough to put slides on could be made to fit your current shelf like in Cary's post; it looks like there's enough clearance on either side of the printer. That's what I'd do.