Fluttermac is best ship, second only to Lyra and BonBon. Then again, Lyra and BonBon are like 75% cannon...

However, it stands to be noted that as the manliest(stallioniest?) of all ponyville stallions, and with the substantial lack of stallions in the first place, Big Macintosh pretty much could have his pick of the litter IMHO. Big Macintosh has Old Spice Guy levels of epic swagger.