"So as a baseline I need a programmer to be connected to a PC and from the programmer a gadget to contact the necessary pins to program the processor."Or a standalone programmer, where the file to be loaded is coming from SD card (like mine) or from other media.Programmed ATmega328P can be purchased from places like digikey.com. I don't know what quantity you need to order to make that economically viable vs just press & hold the programming adapter above. I did 20 cards a couple weekends ago, it is not hard.
* I'm a bit confused..you mention 'IT WORKS!'.... but how can you know if you havent been able to write a bootloader to any of them yet?(or you just uploading a sketch directly to chip?.. no bootloader?)post up some pics of how you have things set-up/connected..and your 'process'..