Well, I've been out of commission for a few days because of my back, but I've made some progress. I went through some tutorials for Eagle and now I'm working on my own board. I went ahead and designed standard connector wirings for each type of output. I based it on the standard RC 3 wire plug and went from there.

At this point, I'm running into a slight design issue, which is I²C running both 5v and 3.3v devices. Since the the 1 device I will definitely hook up runs at 3.3v, I'm partial to that, though I want to be able to hook up 5v devices in the future. 1 suggested solution on the internet is to use a logic level converter. According to this arduino page, there are some basic designs for a logic level shifter. I was able to obtain a couple SMD N-channel Mosfets off of some scrap circuit boards I had laying around. I should be able to integrate a logic level shifter on board of the shield.

I've been looking into using SMD parts because I can already tell the board is going to be pretty packed. I'll need to see if I can find some through hole mosfets for prototyping purposes as well. Anyways, I'll continue working on the design and hopefully be able to make a simple prototype for the level converter.