Before you invest a lot of money, I'd just try out the tire sizes you intend to ride.
What size of tires are you running now? 700x25? Your tire clearance will go away quickly if you go any bigger than 28s. You'll be rubbing if you put on 32 or 35mm tires. And, no clearance for debris. You may also find it a pain if you have to deflate the rear tire every time you want to mount/dismount it with the horizontal dropouts.
You could go with 650b wheels/tires, but may end up with brake reach problems, especially if you intend to swap between 650's and 700's.