Wow - wasn't expecting this much attention, what with the front-page and all - hello everyone!
The mention of automated timezone retrieval made me think about a more 'packaged' version of this gadget. (At the moment, it needs SSH access to get things going, it's hardly a power-up-and-leave-to-buffer device.)
WiFi configuration options (base station ID and key) in a text file on the FAT32 boot partition, then using DHCP and NTP then geolocation to get networking, time and timezone - presumably I could have a read-only partition with a cut-down Linux installation for the software, then a difficult-to-corrupt FAT32 partition for the data? Might make powering-down easier...
Another idea I've had - to avoid modifying the radio too much, have it all remote-controlled - via an utterly prehistoric TV remote control. Anyone know of something with chrome, wood effect or similar?