For things such as a PIC programmer, just obtain a correct design and implement it. There's not really much need to modify existing designs. It's your circuit that matters, not the programmer.
I used Patrick Touzet's ICD1 design which uses a charge pump design to impressively obtain 13V from a 5V. You can google around for the design, as everything from the schematics to the gerber is provided. The wonderful thing about running off 5v is that it can run off circuit power (where your PIC would require a 5V anyway), hence reducing the need of an additional power supply.