Looks like proprietary extrusion similar to 80/20 t-slot extrusion in function. You can get it in generics now (amazon / ali express) or from the likes of McMas

Looks like proprietary extrusion similar to 80/20 t-slot extrusion in function. You can get it in generics now (amazon / ali express) or from the likes of McMaster. Going with McMaster prices for quad slot and by the inch puts the frame with hardware at around $500 by my estimate. Probably another $100 for the top if your having to get material and do the laminate yourself.