Turn off cellular and wifi on your phone. I bet it won’t last more than a few days anyway. I don’t think radio power consumption is the barrier keeping us from weeks-long battery life.
Turns out stateful firewalls aren't just a security factor on mobile internet connections.
I did have an experience with my phone being suddenly used by random internet users. I had ampache running on my n900 (maemo/debian-based) and somebody found it on the internet and started streaming my music. :D I had a higher-than-normal amount of battery usage for a few days so I decided to see what's using it and discovered that my music was being played and downloaded.
Well sure, then it's like a tablet in standby, which similarly can last a month or so.
But it's not going to last more than a day or two if you've got the screen on, playing games, watching movies, using apps offline.