The only thing the output needs to do is switch on that 5 volt supply.
I guess I can let the "secret" out as I'm sure I cannot get a patent on it...
This circuit and power supply will simply activate a USB powered GPS that has logging capability. Here's a link to the GPS:
http://www.amazon.com/gp/product/B001GG06DI
When that GPS has power applied to it, it gets a GPS fix and starts logging.
The idea is that I package that all together, put in a waterproof box (guess the Altoids box wouldn't work then), put a strong magnet on it and use it as a tracking device. All self-contained, no external power source needed. You could then put it on some metal object (a car, one of your delivery trucks, etc.) and retrieve it some time later (days, weeks?) and find out where it's been. You could even build it out with more goodies and have it transmit ham radio signals when there is movement.
Of course, there are factors to consider:
1. Battery life (hence the power saving Picaxe/motion sensor circuit)
2. Orientation to the sky so it can get a GPS fix
3. Protecting from the elements.
So, that's where I'm at. Looks like that sparkfun project might work nicely.