First off I want to thank danielhr77 for starting and participating this thread:
http://traxxas.com/forums/showthread...-4-Channel-Mod

I was doing some research and stumbled upon it... because of this thread I now have two 5 channel 2238's! One was 5 channels straight off, the other I was able to change from a 2 into a 5 using the ground to vss method.

I have a Summit coming in the mail on Tuesday that should have a TQi 6508. Since I have no personal desire to use the TQi, so I plan on trading and/or selling it for another 2238 plus cash; or two 2238's, depending on what I end up needing... probably two 2238's because I like having a controller for each of my RC's.

My goal is to have a remote that can control the following from a single remote:
ESC
Steering
Steering selector for PunkRC's Steering Computer
Front Locker
Rear Locker
Transmission High/Low
LED switch (Rx operated switch)
Fan switch (Rx operated switch)
and possibly a Horn, space allowing

To do this I would need at least a 8-9 channel Rx/Tx which I have found nearly impossible to find in Pistol Grip form. The few that I have found with more than 4 channels are extremely expensive.

Since I feel qualified to perform the procedures to convert a single 2238 into two 2238's in the same housing, I decided that this is a project that I can tackle without too much difficulty... as long as I have someone to help with a few questions along the way. lol

They only hurdle I have at this moment is where to put the batteries as I have chosen to place the board for the second controller below the original controllers' board; displacing the battery tray.

Here is a picture of what I have in mind for the finished product:

Subject to change, of course.

This is what I have done so far...
1) I have been able to convert both of my 2238's to 5 channel Tx's.
2) I have figured out the circuit board... to a point. I still have some playing to do.

What I need to do...
1) Figure out where to put the batteries.
I have chosen to place the board for the second controller below the original controllers' board; displacing the battery tray. One option is getting a project box to house a 6.6v LiFe battery.
2) Figure out the rest of the circuit board... how it operates the channels
3) Figure out if the Tx can handle 6.6 volts.
4) Figure out what pole/throw switches I am going to need.
5) Find a good source (not much of anything locally) for the switches and project box.
-plus more, I am sure. lol

Any help is appreciated!!