Connector choice is influenced by your application.

Military style connectors and CPC type connectors are available in panel mount styles for mounting on the firewall or other flat surfaces. However, they look like crap unless they are on an aircraft or industrial machine.....OR if you can hide the connector low or to the side...they might be good.

Delco makes a Weatherpak connector like this
http://www.amazon.com/Delphi-Packard.../dp/B0017NR110
that looks more automotive. You can buy Weatherpak components and Metripak components from DelCity.com
The link that I attached above is for a 20/18 ga wire and 22 pins....not enough current capacity for much if you have a higher amperage circuit....do a search on GOOGLE for
"bulkhead connector" plus the word "automotive" and you should get quite a few hits.

You should start by making a list of all of the wires that you want to disconnect and the wire size or current......that way, you can determine if you need one or more bulkhead connectors and the wiring size for each circuit. Make sure you add some spare circuits...you will use them eventually.

Hope this helps.

mike in tucson