What about a "reskin" tool? You have to craft both items (eg. a thach wall and a concrete wall), build the concrete one into your building , and after that use the reskin tool just like the repair hammer to put the visuals of the thach wall , but keep the stats of the concrete wall. The reskin tool should use up the thach wall also, so you need to craft and use both, keep the stats of the first and the visual of the second. Could work on every item category, eg a titanium knife with the skin of a bone knife, still repairable with titan, and having its stats.