wouldn't it be possible to make a bootloader for other ATmegas then the 168/328/1280/2560? Perhaps even some ATinys? You could burn the bootloader with ISP and download the sketches with the FDTI cable. It doesn't need to be a new board for every ATmega/tiny, just a bootloader available.
This would make it much more economical to build projects what one need a few Inputs/Outputs, or many Inputs/Outsputs with only one chip. Or use features like the onboard Can interface of some ATmegas.
I can't find any, just topics like mine, what should I search for?
But: I thought more of official bootloaders for other chips what you can burn from the arduino IDE. I'm not so much into Hex files and so, but I have managed to burn a bootloader on another ATmega328 from the Arduino IDE.
and not all of them can use a boot loader, for example most tiny's do not have a boot loader available, so you need an ISP programmer, which can be an arduino