I found this site on Focebook:
So there's this new thing: the unhotel. And we're it. We give you the chance to stay in someone's place while they're out of town. Live their life for a few days and nights. Act like you own the place. Because, for a few days, you do.
There are many sites like this. From a quick search, I found a property for £125/night and up. At those prices, it's not competing with hostels, but home rentals is a trend to watch.