After nearly two years, I refreshed this project again.
Apparently, Microchip introduced new programming specification for newer PIC devices, like PIC16F1xxxx and PIC18FxxK20 and PIC18FxxK22. The old format was LSB first, either with mix of 8/14 bit long words (for PIC16Fxxx) or 8-bit long words, but a lot of direct instructions entering (PIC18). This seems to be unified now (see the famous XKCD comics) with MSB-first and 8-bits only words. Nice initiative, only if there were already a few different formats among PIC devices.
Honestly, I was too lazy to implement it, but there is already quite a few "new format" devices in the wild, so I finally got myself to add it to pp3 programmer, so here you go. Only PIC16F188xx are added, but more will follow.