Hello elektryk,
Try searching around - this recent thread springs to mind:
Also these:
To summarise for you, the problem with universal programmers isn't driving the pins, it's knowing the programming protocols for the devices you need to program. The manufacturers often guard this information carefully. Simple E(E)PROMS, MCU's etc are easy because the protocols usually *are* available (and simple). A bunch of 74xx logic may suffice.
For more complex devices, like CPLD's and FPGA's, the programmer will probably use a CPLD or FPGA itself to drive the pins, plus some buffers and/or DAC's for high-voltage programming. Having the wiring diagram (which is probably fairly simple) would be useless without the (probably protected) code.
I have a Galep-4 - it uses an FPGA inside and programs most E(E)PROMS, Flash, MCU's and GAL's.
FoxyRick.