Well, that was a surprise! Went to load up youtube on my TV today, and it forced a firmware update - ho hum. Let it finish, then discovered it'd updated from VieraCast to Viera Connect! So firstly I get the thing I really wanted (internet radio - Shoutcast app, it's really good), and secondly, there's the VieraConnect Market so you can link to additional applications!
Time for some more tinkering I think :D This TV just got a whole lot better!
Well done Panasonic :D