Does anyone have any info on whether MPLAB has RS232 compatible programmer
support?

Having downloaded a number of programmer schematics, I've found that a
couple (Serpic & David Tait) that are very similar to the Velleman K8048 and
wondered if this is some sort of industry standard.

If anyone is interested, the examples including Velleman K8048 schematic are
easy to find with google.

The RS232 connector is as follows:

Pin7 (RTS); CLK/RB6/PGC
Pin4 (DTR); DATA/RB7/PGD
Pin8 (CTS); DATA/RB7/PGD
Pin3 (TXD); Pin3 & Pin9 hardwired together
Pin9 (RI); VPP/MCLR(NOT)

Each signal has a transistor buffer/level converter between the RS232 +-12V
and PIC logic levels.

TIA.