yes! there are a number of folders that can handle rides of 100 miles or more. some are even considered more comfy than full sized bikes! For example, i own an Airnimal joey, which does not fold as small as other bikes but comes with its own carrying bag which is fine on trains, subways, etc. it has 24" wheels and I have toured with it for weeks and done upwards of 80 miles a day.
Bike Friday, of course, is another great company with a range of folding bikes suitable for long rides. There is also the Swift folder, the Birdy, the Mezzo or Ori bikes, Moultons of course, and even a few of Dahon's models are ok too. Expect to spend upwards of 800 dolars for a suitable ride though, even used, these bikes are not cheap.