If you want a compact folded unit, consider Brompton or Merc.
If you want a "real bike replacement" that folds, try a Downtube FS and upgrade it to your satisfaction or go with a more sophisticated out of the box bike (Dahon, KHS, etc...)
If you think a 26" wheel will work on your travels, consider a non folding bike. The trouble will be the same.
Just my opinion.