When Chris questioned the purpose behind adding the extra FM board to the Vex remote he gave me a better idea.
As you can see on the back of the remote, I have marked a black box. The hump in this area will have to be removed with my Dremel to give me a flat area to mount a small box. This is the box from Radio Shack: http://www.radioshack.com/product/index.jsp?productId=2062279&cp=&sr=1&origkw=plastic+box&kw=plastic+box&parentPage=search
The box will become my adapter for the extra crystals, 1 mounted on each side of the box. The white picture shows the layout of the crystals and below them I will mount a mini 3 way switch. The switch will allow me to choose which crystal will be active and which Vex micro I will be controlling at that time. I have allready tried wiring the crystals and they don't seem to know they are being wired different than the way they fit stock.
I will loose 1 Tx crystal, Because I need the plug to fit into the original spot. And you can see the inside of the original crystal in the pic.
Also the box is small enough that it will not get in the way of the 4 digital buttons on the back.