Portable Arduino to load sketches into other Arduinos


I was wondering if this is possible. I have seen projects where Arduino's where loaded via Zigbee or Bluetooth and even IR, so at this point, to pass a sketch that is already in an arduino to another one without a pc, just pressing a button for example, seems very doable. I can't find any guidance online. Has anyone got an idea where can I start from?

Thanks in advance

Here's one nifty approach that Nick Gammon developed

Seems pretty close. I guess the serial.print can be on an LCD and then you wouldn't need a PC. am I right?

LCD could be made to work.