retrolefty:
usually are told they will have to find and send the .hex file of the compiled sketch and have the users install the arduino IDE so they will have a copy of AVRDUDE and it's support files and some kind of batch file to run make scripts, etc. At least that is how I recall all the messy details.
I think all the ingredients are there to enable a script to install the USB drivers and then install/run a standalone avrdude. It could be invoked either as a manual batch file, or an autorun batch file, or an executable installer. But it's not an easy job.