...stealth delegates who would follow their pledge to Romney within the scope defined by the rules (and then vote for Dr. Paul once freed from the pledge on the 3rd ballot or whatever) from stealth delegates who are intending to break their pledge from the get-go. You also need to differentiate between what 'pledge' means within in each state, rather than conflating the California rules to apply to everyone else.
You are not taking a blood oath to vote for Romney on the umpteenth ballot at the convention are you? That is over and beyond what 'pledge' means in this case. You can honestly fully intend to carry out your pledge within the rules and then vote for Dr. Paul once those same rules allow you to.
AND if the delegates at the RNC have the right to change the rules prior to any ballots being voted on, and as a result all or some delegates are unbound, the pledge will no longer apply. I think you're getting hung up on the 'best effort' phrase in your particular instance of California rules. Don't try to force that hang-up on other states where there is no such phrase.
Edit: I just went and re-read the California rules...it only says 'best efforts....UNTIL' one of the conditions is met (emphasis mine). Some of those conditions are being freed from the pledge; not just seeing the candidate nominated. Even in California, it is completely honest to pledge to follow these rules and vote for Romney until you are freed, and then vote for Paul. There is no dishonesty involved.