I thought the same thing and wondered why it could not be done. I asked all the weather vendors the same question, why not an internal antenna? Some thought the carbon lightning protection would interfere, some just had not thought about it. But none of the vendors at OSH were very excited about this approach.
Arnav said no, needs an antenna outside and that they were not working with Cirrus on it (I read that as very unlikely to get weather on my Arnav - ever much less soon).
Avidyne is using a coupler (mentioned in another post to avoid the new antenna). Shown on a price list as a DC50 “Antenna Datalink Coupler”. Cost is 495.00. Think it is not ready until November. I would rather do that myself.
WSI said they might test it if someone would work with them, but that they did not feel overly excited that it would work. They are not working with Arnav, but are working with Avidyne.
Garmin said, needs an antenna.
As you can tell, I was specifically looking at weather products.
Frankly the best currently available product is AnywhereMap. It is portable and does not require an STC, but I do not want all the wires and electroncs loose in the plane (like a PDA, a GPS, a box they provide and a Sat Cell phone. Its a wiring nightmare…
Ah, the pleasure of being an early adopter…