Back in Xtracycle's FreeRadical days, we made an adapter that allowed you to install 700C tires on the FreeRad, using the rim brake mounts for what would otherwise be 26" tires. It looks like this:
Since the FreeRad is no longer in production and the new Leap is compatible with disc brakes only, this adapter is no longer in production and pretty tricky to find. Your best bet if you are really on the hunt for an original FreeRad 700C brake adapter is: eBay (they pop up from time to time), Craigslist (AdHuntr is 3rd party site and a great way to search in cities outside your own) or a Google search to see if any 3rd party sites have them (which is pretty rare). If you are one of the lucky few able to get your hands on a 700C brake adapter, the installation guide can be found here.
Another option would be the Motolite made by Paul Component Engineering, found here. It will do the same thing a 700C brake adapter did and retails for $146-$156. It looks like this (pic from the Paul Component's site):
Have further questions about the 700C brake adapter? Shoot us an email at firstname.lastname@example.org and we'll do our best to get you ready to roll on your FreeRad!