Update
6/28/2015
Mounted a MegaDrive v5 to my rev C board. It was my second time soldering a v5 megadrive and I have some tips if you are going to do the same.
-Only desolder the bottom 16 pins, Leave the top 16 so that the bottom side of the pins stick out through the megadrive holding it in place.
-Or instead of desoldering, you could just carefully grind off the bottom 16 pins with a dremel.
Working wasp
also if you use a megadrive v5, make sure that one of the memcard gnd mount pin isnt shorting on the ffc cable. Mine was and caused the wasp to first tell me that the region switches were incorrect and then after a restart from that it would freeze each time I rebooted.)
Got the bottom side triggers in place:
I also decided that I will cut up the controller board even more.
Im going to be using the abxy and dpad portion cut from a 3rd party controller, and the c-stick, left analog stick and IC from a official controller.
ABXY portion:
Here is the IC board cut I plan on doing: (Hopefully I can solder directly to the vias, with this cut I will get around an average of ~2 vias per trace. Just in case I mess up)
I also worked on how I am going to wire the triggers. I am going to have 2 pushbutton switches for each trigger. I was originally planning on having one for half press and the other for full press with a transistor method. I tried some optocuopler ideas but didn't get anything to work. I then tried some different ideas with the transistor method and using diodes but the drop across the diodes caused some problems.
So I ended up just trying out the old school 2 tact method, which is what I am going to use for now. I tested it out on super mario sunshine and I like the effect it caused. You aim with one press and then shoot with the other button almost as if it is like a new feature.
I also tested on mario kart and the power slide works just fine. I am not sure what other games will be affected.
Let me know if any one has recommendations if I should or shouldn't use the original gc regulator board to power my 2 5v fans and audio amplifier.
I am getting close!