Can you state the final authority for that assertion as I cannot find one. I guess it all depends who you ask and in turn where he got his information from. The local simulator technician maybe? A check captain who is the airline technical guru? One theory I was told was the takeoff trim setting ensures the aircraft will be in trim at V2 plus15, with one engine inoperative. If that is true, it would mean 99.99% of all takeoffs (all engines) the aircraft would be out of trim the moment VR commences?

You're probably correct about V2+15 with an engine out. The 757 is NEVER in trim on a normal takeoff. You need to adjust it after takeoff. So we asked out tech folks about the trim settings because it was off. They explained that it's not set up for rotation or the thrust settings we use on 95%+ of our takeoffs. We, tongue in cheek, said "why don't they just say 'ITG' (In The Green) on the checklist because it's always off."