This should be a requirement for all keyboards and mice - they should be dishwasher safe. It's a great idea. I read it first here and if you want to buy one check out the maker.
They were originally designed for the medical professions where several people are using the one PC. Nasty germ gathering potential there. So thinking of nasty germ gathering, they'd be idea for any family with young kids that love banging on the keyboard while eating toast. Of course that will usually mean banging the keyboard WITH the toast (while watching the Hippo and the Dog singing "The Lion Sleeps Tonight").