Ross, i know yer frustrated with this problem and feeling like you have done lots of stuff that hasn't fixed it. keep in mind the fuel tank issue would have had to be addressed anyway, and now you know all yer lines are good.
when we worked on it at my house, and when we were on the st croix i believe it was verified as a fuel issue (at my house observing low fuel pr on the gauge, and on the st croix by Jeff observing no accelerator pump squrt after it killed.
i realize the only component in the fuel system that has not been bypassed is the filter, though i doubt it could be that.
also keep in mind we could be struggling with more than 1 issue or bad component, and something that is new or rebuild could still be suspect.
lets plan on installing fuel pr gauge and Jason's spark tester and test those things tomorrow. i am going to try to get out of the house by noon as i want to water test mine some on Thursday as well.