Considering how much I like the solidity of a good steel plate ... I assume a good stone keyboard (but would probably want zinc keys not stone ... probably) would be enticing and a great item for the elitists to say "hey look, we have WAY more money that you!
Which would only make all the rest of us want it that much more, right?
But a stone plate. I dunno. Seems likely to be brittle. Also, don't drop it.
ever.