Well I've made a bit of progress so far. Here are my latest findings but first a quick shoutout to some of the guys on arduino forums for their help.
I think it's possible to connect the OBD II via a RS 485 serial cable and port. You can make your own serial cable with the obd II connector in the current parts list or buy one like this
https://www.sparkfun.com/products/10087
I will most likely make one myself due to some of the things I've found researching. You'll also need a serial port like this one
Nextrox® UART TTL Serial Port TO RS485 Converter Adapter MAX485 SMD SOP8 For Arduino:Amazon:Computers & Accessories
This is important though if you're looking for a serial port you have to find one that matches these 2 criteria!!! 1 It has to be a RS 485 serial and, 2 it has to be for arduino.
I won't update the parts list yet because I'm still working on a few issues that will have to be worked out before the list is definite.
Currently the issue is that these protocols have too high of voltage for the arduino:
SAE J1850 VPW (Variable Pulse Width at 10.4/41.6 Kpbs, single wire)
ISO 9141-2 (Asynchronous serial communication at 10.4 Kbaud)
ISO 14230 KWP2000 (Asynchronous serial communication up to 10.4 Kbaud)
Once the voltage issues are sorted out I'll be able to get the parts and try this out to see if this is a real option for all protocols until then though this is a possible option. Hopefully though this will be good option for standardization over all protocols.