Actually, that is not that far fetched, simply datalink all aircraft wx radar returns and build a composite real time picture. Now, the only thing preventing that at the moment is cost and datalink capacity, but it is possible right now.
There are systems out there that link aircraft measurements, and transmit between aircraft. So far, it is the basic winds aloft and a few other parameters.
AMDAR data is sent from most widebodies, and other ac equipped. It is just a matter of uplink, which is becoming much easier these days due to the IFE and Ku band transmission capabilities.
Several services offer the winds aloft direct to the flightdeck, pilot just has to accept. The winds are broadcast directly from the aircraft, and frequently. This information is then uploaded to the other aircraft on the route.
Southwest Airlines in the US has the system active, and the drivers love it.