I wish this was available for OBDII. It is software for Buell motorcycles. With a USB to TTL serial cable, it communicates directly with the motorcycle's ECM. You can change any value. Which means of course that you can screw yourself up royally, but if you fetch the original EEPROM, you can save it to flat file and burn it to CD. You can always go back.
This is the overview. Pretty basic, but notice you have the O2 (EGO) voltage and correction factors for closed loop. This sets the Adaptive Fuel Value (AFV) the ECM uses to correct the mixture. It tells you how far off you are.
ECM Runtime gives you more info, in realtime. Sorry I don't have a running screenshot. It's cool.
These are the fuel and timing maps. You can manipulate any cell and burn it to the EEPROM. It also has realtime feedback on which cell the motor is on at any particular time. You can show the CL regions, WOT regions, etc. (which I did in the screenshot, I did not draw these lines).
Lots of control here: