I don't see a sumberged pump as practical, and I don't think cavitation is a common issue with large fuel lines, but u may be on to something when u suggest putting the pump next to the tank, eliminating the UAT as a possible cavitator.

One would have to use something more substantial than a simple plug to cap the line used for fueling though !

Interesting idea.

Oops, just thought of a problem. One had best use a rigid UAT, lest the thing cause response lags as it expands/contracts under varied pump pressures.