This thread has been entertaining to say the least. :-)
I had two initial thoughts about this when I first read the original post.
1) I'm always amused by all the people afraid of propane and wanting an all electric RV. I recall the long running argument George Westinghouse and Thomas Edison had over DC vs AC and some of the shenanigans they pulled trying to scare people onto their side of the argument. There are still people today, generations later, who have fears over electricity that are rooted in those arguments. Obviously those arguments don't scare the OP which is good!
2) If you have to ask if something can be done because it's not an off-the-shelf commodity, then it's probably something you don't want to do.
And for what it's worth, I'm an EE although my career was spent working in computer engineering, not power. I know just enough to wire things up correctly at the house and in my RV, and some might debate how good that knowledge really is. Unless I knew I was pulling power from two different legs I doubt I'd try this, but I don't have to since I ran 220v/50a to my RV garage.
