PIC-based PIC programmer?

Hi,

Does anyone know of a PIC programmer which itself is based on a PIC
chip, and which only uses the bare minimum of parts?

Conceivably, a PIC-based PIC programmer would only need:
 - a PIC
 - a crystal or resonator
 - a MAX232 or equivalent, plus charge pump capacitors
 - maybe a transistor or two, in case the programmer needs to
   bludge some +12V from the MAX232 and switch it into the target PIC
 - a couple of buttons and LEDs.

If a PIC chip had the programming code plus a bootloader, it would only
need to duplicate its own code into the target PIC, and then could
function independently of the host computer when it's just being used to
burn other PICs.

Such a thing, published with PIC code, host code and PCB artwork, would
be a human-facilitated benevolent 'PIC virus'.

"Give your friends a pre-programmed PIC, together with the PCB artwork
and host software". Would be a brilliant geek birthday/xmas present! :)

So, does such a thing exist?

-- 
Cheers
David