Re: Audio cast dongle - yes please
I've got an Arcam miniBlink in the living room, which is great with a phone that has aptX. But at £90 it's probably not the sort of thing I'd go out and buy myself.
But, something that sort of size must surely be possible - or even a matchbox size, with external wall-wart PSU - for audio. Roll them out for £20 each, and I'd have one in every room, especially if they could sync network playback.