I'm currenly adding some "extra" PIDs and conversion functions I found. I'm not quite sure what they are if they are just more standard or extended, if they only work with specific vehicle etc., but I found them here:
http://www.ghg.net/dharrison/OBDScanAPI.PDF in mode 1 PID 0x21 and up. I'm assuming there more OBD II standard codes possibly a newer revision?
I'll be testing them out later today. Let me know if you know anything about these PIDs.