Off the top of my head, you might be able to use an inexpensive DSLR with an EyeFi (
http://www.eye.fi/products/ ) SD card with an infrared transmitter (
http://www.home-electro.com/tira2.php ) attached to a computer.
My Nikon's DSLR shutter can be triggered with an infrared transmitter and apparently it is fairly easy to make most IR transmitters send the right frequency (wavelength) to trigger the shutter.
A script could then be written on the computer to work the system.
Maybe this will provide you with some ideas?
I like the idea a lot and it sounds like an application that might be adopted by many mail order businesses! You should consider somehow trying to "own" the process.
Best,