[Giorgio Vazzana] turned his Raspberry Pi into a PIC programmer using a rather small collection of common parts. It supports about a dozen different chips from the 16F family. But we’d guess that software is the limiting factor when it comes to supporting more chips.
Generally the problem with PIC programming is the need for a 12V supply. He chose to use an external 12V supply and a 78L05 linear regulator to derive the 5V rails from it. With the power worked out there are some level conversion issues to account for. The RPi provides 3.3V on the GPIO header pins, but 5V logic levels are needed for programming. He built transistor and voltage divider circuits to act as level converters. The programming software bit bangs the pins with a write time of less than eight seconds per 1k words of program data. So far this does not work with ICSP, but he plans to add that feature in a future version.