Are you wanting it removed because of health issues or possible health issues in the future? Because research has shown that microchips do not cause things like cancer even though a small minority think it does, this is completely unfounded in cats and dogs.
Having it removed will involve a surgical procedure, and an unessersary one at that which in my opinion only is cruel to do to any animal. Its like saying you don't like they way their ears look so lets shave a bit off
I would also ask myself why all the vets you are speaking to are refusing to do this procedure. Do your dog a favour and listen to the advice of these professionals!!!!!!