If you have the data plate and the drawings you can rebuild an aircraft, but it needs to be worth the cost and effort of doing so. Arguably, a new Spitfire would be worth building. As to engines, the CAA recently issued an AD on the Rolls Royce Merlin. There's quite a few of them around and there's at least one firm that specialises in overhauling them using the OHM and manufacturing new parts as required. Then there's the Packard versions...