[URY914]

I have used several different items for tops over the years. I'm currently using a commercial grade hollow metal door. This is not the same as the light weight ones from HD but the big bad ones from a door supplier. You can pick up a "slab" pretty cheap. They always have some in the warehouse that were returned or were machined wrong. They can be up to 4' x 10' but also come 36" x 7'.

Also look at a solid core wood luan door. They are at HD and are unfinished. They'll be from 30" wide to 48" wide and from 6'-8" to 7' tall and can be cut down to what ever works.

With these you don't need added framing like you would with a plywood top.