I'm not a big money guy, so I can't pull this off, but maybe someone out there knows someone who could pay to do the kind of poll that all the polling companies and media outlets have yet to do.
Let's wait until we see if Trump really does get the GOP nomination. Let's assume Jill Stein will get the Green Party nomination. We know Gary Johnson is already on the ballot. Then we need a state-by state poll, with enough respondents to give accurate information on a state-by-state basis (and Congressional district by congressional district in Maine and Nebraska).
Then the day after the GOP nomination run the poll, asking two questions.
1) If the election were held today, and the candidates on the ballot were Democrat Hillary Clinton, Libertarian Gary Johnson, Green Jill Stein, and Republican Donald Trump, would you vote for Clinton, Johnson, Stein, Trump, some other candidate, or leave the ballot blank.
2) If the election were held today, and the candidates on the ballot were Libertarian Gary Johnson, Democrat Bernie Sanders, Green Jill Stein, and Republican Donald Trump, would you vote for Johnson, Sanders, Stein, Trump, some other candidate, or leave the ballot blank.
Once the state-by-state results are in, do the Electoral College calculations and see who wins. (Nationwide polling is nothing but a beauty contest because we don't vote for President that way; doing electoral-college calculations on a state-by-state basis is the only way to get a true picture of what may happen.)
This needs to be done quickly, so the results are known the day before the Democratic convention nominates its candidate. That way the super delegates, who will make the final decision (neither Clinton nor Sanders has enough pledged delegates to win) will know exactly what they are doing and will be able to meet their obligation -- which is not to support a particular candidate, or to do what's best for America, but, according to the Call of the Convention, "who have the interests, welfare and success of the Democratic Party of the United States at heart, who subscribe to the substance, intent and principles of the Charter and Bylaws of the Democratic Party of the United States (note that it doesn't say platform), and who will participate in the Convention in good faith."
The only interest of the Democratic Party here is to win the fall election, not the summer nomination. If the polling shows Sanders will do better in the fall, super delegates should support Sanders on the first ballot.
This should not be done as a Sanders campaign survey. We just need someone to step up as a private individual (or corporate "person") and pay to have the survey done, then just stand back and let the results fall where they may.
Anyone out there know anyone who might want to help pay for this?