Wake-On-LAN or other method
I want to be able to wakeup a sensor remotely, kind of like WOL. Is it possible to do this via the IRQ pin on the radio that is connected to D2 (interrupt 0) on the Arduino? I saw in the radio wiring diagram a note about the IRQ not being used, is that still the case with the Dev branch?
Short answer: No.
Slightly longer answer: If you are sleeping to conserve battery you would need to power down the radio, so even if MySensors supported interrupts there would never be an interrupt because the radio would be sleeping as well. The power requirements for the radio in receive mode are too high for battery use.
Long answer: Read the following earlier threads on the same topic: