Hi Andrew, this might not be what you're looking for however here is what I made.
The top is 2 X 6 cedar with M&T construction using Titebond III for glue. Once the top frame is glued the underside cleats are glued and screwed to the frame.
The raised bed is made from 24" square patio stones, they don't rot, the string trimmer doesn't damage them. The slabs are set 2" below grade.
You could supply the frames, leaving your customers to supply the slabs...............Regards, Rod.
Raised Backyard Beds.jpg