has anyone done anything to the effect of adding a larger replacement fuel tank? Added a secondary tank plumbed to the main tank?

I'm only looking for feedback on those that may have attempted something like this , not those who will ask if I can't find a gas station w/i 275 miles please. Yes I can. However I have just completed a 4100 mile road trip and I'm about to go on a 5000 mile one and would like to see if anyone has done anything to increase the range of the X yet.

thank you in advance....