About 35 years ago I made a bed for my daughter as she outgrew her crib. Ignorant of standard sizes I simply built it to my taste. Now it is a white elephant, terribly uncomfortable, but we can't bring ourselves to throw it out. Yet. The bottom is a polyurethane cushion on a sheet of 3/4" plywood

My question is whether I can order proper couch springs anywhere made to an odd size: the plywood is 30" by 73.5". Since it is too narrow to be a decent couch and the back is too low to provide any support I have my doubts, but do want to look into the possibility.

Thanks,.....