One nice thing about XBMC is that streaming to a new client is as easy as putting the back-end's (tvheadend) hostname, port, username and password in the client and away you go. On Android phones and tablets, however, there wasn't any official XBMC client, so I found TVHGuide instead. It's an apk (not in Google Play) that talks to tvheadend to get the channel list and presents a basic interface that passes on any stream to a suitable video player. It works fine for SD channels, but seems to fail with any HD channels, so I stopped using it.
However, the good news is that XBMC has now been ported to Android! It's apparently the full client - including add-ons - and I hope someone remembers to build it with the PVR add-ons! Quite why PVR facilities are still considered optional to the core XBMC code is completely beyond me, especially since every other client media centre software in the world seems to have them.
Of course, we're now in a race against time for the first beta apk's to appear before the Olympics start. Let's hope that they work on my HP TouchPad running CyanogenMod 9 because it will allow me to wander around the house with a tablet showing live Olympics (on a different channel to the plasmas). In the meantime, I'm playing with the official XBMC remote control app for Android, though it's missing the streaming element sadly.