The cost of parts for this looks to be about $50, and you're posting to a group of tinkerers (and skeptics). Those that think it's a good idea (like I do) will go out and do it themselves--or have already done it, like I have. I use manual switches and/or simple plugs and receptacles for switching sources.
I'm a big fan of 30A+20A aux input, which I have now on my current TT. However, I now suspect that the ideal setup is a true 50A that runs off only one leg, while the other leg is used as a switchable source for powering aux items--electric heaters, additional AC's, etc. To be clear, when true 50A is available, the aux items run off the 50A leg. But when using 30A or gennies, the aux source can be switches to 30+20 or a second gennie.
