I've think figured this out. It is remarkably genius (for me) if it does.

The problem I've been having is that I want it all on one stick like how I have it now but I am no electronics engineer. However, thinking about it, any single channel ESC that can drive the low end of the relay should work and you can get ESCs that go up to 30 or so volts with relative ease, it is only the amperage that is the issue. So then it is time to think logically. If moving the stick one way makes the ESC spin a motor forwards, polarity must be reversed when doing the opposite.

For a bog standard normally open relay, I get the impression which way around the polarity is doesn't matter. So, connecting two low ends of a relay to a ESC means they'll both turn on regardless of which way around the polarity is. So assuming that, adding in some diodes on the low end of the relays (where a set of 4 is specific to a specific polarity, one for each port of the low end of the relay and the other set is the reverse) and it *should* work. Even adding in a variable resistor on the backwards motion is a potential option for a soft return.

I've not tried this yet but wanted to make sure I wasn't being idiotic before committing to this. Does the above sound logical?