I recently bought one of these http://www.hobbytronics.co.uk/wireless/bluetooth/bluetooth-module that is a drop in module to extend the serial monitor over bluetooth, in effect emulating FTDI serial breakout.
The datasheet http://www.hobbytronics.co.uk/wireless/bluetooth/bluetooth-module shows it has 8x programmable I/O ports that can be set/reset using 'AT+PIO=,'. I am wondering if the output of one of these PIO's could be used to reset the Arduino much like the RTS line can on FTDI to put arduino into programming mode for uploading new sketches in a similar way to xbee Xbee Adapter - wireless Arduino programming but there does not seem to be a way to alter the PIO from a remote bluetooth connection. Maybe sending a 'magic' value over serial to a listening arduino could make it reset and accept upload of new sketch.
Is it possible to configure Avrdude to send a 'magic' value and then continue uploading the sketch, would one need some external program to do this or maybe it's just not possible at all?