Where can you find fiberglass or plastic pool coping to cantilever over your existing aluminum coping?

It depends on the pool make. The only one I know of that offers a plastic "coping cover" is Pacific Pools, now owned by Latham Plastics in Latham, NY and it is only for their older "Garden Pools". Your aluminum coping can easily be reconditioned with an epoxy spray paint from the hardware store. If there are defects, fill them with a two-part epoxy putty and sand it to blend with the rest of the coping before painting. Mask the coping off with painter's tape to keep from painting the deck or liner. Hank4pools@aol.com