I have an early-70's Harmony, one of the few made with laminates (I guess I'm just lucky!) The top has bellied so much that the corners of the bridge away from the sound hole are loose, .020 on the treble side, .025 on the bass. It would seem to be a candidate for the JLD which has been recommended here, but I wonder if anyone knows whether it will work on a ladder-braced laminate top.
I sort of hate to invest $20+ in low-value guitar, but there ought to be some way to make it a decent-playing beginner guitar/beater.