You could take my bootloader uploader:
Just put it into a plastic box, provide power, and run the ICSP cable out a hole. That uploads a single bootloader kept in its memory, and does the fuses.
In its current form you command it to write the bootloader with serial comms, but you could have it test a button and do it. And have an LED or two to show when it is programming and when it is done.
What you posted looks OK though. Note that the thing you posted needs a "PC uploader" to put the sketch onto it in the first place.
So, not too bad for $189.