mikedehaan:
I think we've exhausted the Arduino nature of this topic, so this forum is probably not the best place to proceed.
That is only possibly true if the processor is an ATtiny20. SPI programmable ATtiny processors (e.g. ATtiny84) are very popular in the Arduino world. They can be programmed easily using any Arduino compatible board. There is even a forum section dedicated to the pursuit... Microcontrollers.