I tried joy2key, xpadder (I only looked at the older free version) and autohotkey and a couple of other obscure ones and did not have any success with those because of the directx connection. They fail for the same reason macros and key reassignment on the G27 profiler fails.
Here's how you know where you are in the MFD. Every time you open the MFD or go through the pages until you get to the "Change" one (I'll use that name to describe the settings page), it always goes to the top and has Fuel Mix selected. So, the first thing you have to do manually is navigate with the MFD button to that "Change" page. Now you can use a macro button. Let's say you want to have a button that sets the mix to rich. No matter which mix is currently selected, you only have to go right twice to get to rich. The fuel mix selection does not wrap around and it stops when it reaches rich no matter how many times you press the right button. Similarly, if you want to switch from anything to standard, you only have to go right twice and then left once (you could go right 100 times and then left once and you still get back to standard).
How about a brake balance button. From the "Change" window (where it always opens with fuel mix selected) you need to go down once. So a button to move bias forward is down and then right. As soon as you hit that key and it goes down and right, you want it to finish by going back up once. This puts you back at the fuel mix selection so any additional presses go down right up (advancing the bias and returning to fuel mix).
The two critical things here are that you have to manually navigate to the "change" page before you can run any macro and that each macro has to finish by returning the selector to the Fuel Mix option. That gives you a fixed starting point. So, for example, if you wanted to set differential higher, you would navigate to the "change" page and press your Diff+ button, which would do a down down right up up. If you immediately wanted to change bias forward, you press the Forward Bias button and it does a down right up. The only "special" one that I remember is Next Tires. Next Tires wraps around so you might only need one button to move down to that selection and then go right through the selections. I haven't gotten that far. I don't remember how wing fix works either off the top of my head.