“Might have to switch to an inline electric pump to prevent ethanol-related problems.”
You have to go in the tank in order to keep the pump cool enough to not vapor lock. Heat and or altitude will exacerbate it.
Yes, there's an increasing market for "retrofit" fuel tanks for classic cars and trucks, fitted with in-tank pumps, slosh baffles and a fuel level sending unit matched to the vehicle in question. When plumbed with hard lines for supply and return, these rigs allow for EFI systems to be used (or carburetors, with the appropriate pressure regulator up front).
A big plus is the fact that these EFI tanks have all the fittings (except the drain plug) on top. Many old cars had the sending unit and fuel pickup on the lower front surface, sealed by a rubber gasket and a lock ring. That's another (big) point of vulnerability when in constant contact with ethanol blends.