Pop Up Camper Double Height Bed Track. Does it exist?

[indiedog]

Hi All. I've got a pop up camper design and for it to work I need an alum' bed track, but a double where one bed frame can slide in over the other. I didn't think they existed but I remember seeing a thread on here ages ago which showed exactly that on a pretty old pop up. The idea is that I take the mattress off the lower bed frame and put it on the higher bed before sliding both ends in. I'd be looking for some new stuff preferably but won't say no to second hand. If anyone knows of such a thing I'd love to get some details.

Of course I could get something made but would love to see if it's still out there.

Thanks, Indie.