Assuming that such a card did exist, it could have been quite the boon, depending on how much Romney enjoyed McDonald's. In 2012, a McDonald's hamburger costs $1 as does a small order of fries, and a small shake runs $2.49 -- a $4.49 meal (plus tax). Assuming that the cardholder obtained the card at age 25 (old enough for George Romney to prove himself worthy of such an honor, albeit still precociously) and ate one McDonald's meal a day until death at the ripe old age of 100 (dubious, considering this gratis diet plan), the McDonald's for Life Card would have been worth $122,913.75 over those 75 years, not accounting for inflation.
And so now, weeks later, it seems that the world may never know the details surrounding George Romney's McDonald's VIP status. Sorry, Mitt - your childhood anecdote to "unzip the real Mitt" has only added to the intrigue.