The parts bin has both single digit and 4 digit (multiplexed) 7 segment LED displays in it (use parts search to search for display). I know there are 2 digit and 3 digit multiplexed 7 segments available but there don't appear to be Fritzing parts for them (at least in core, a google search and a look at projects may turn something up). If you aren't cost sensitive and want something cool have a look at these rgb 2 digit displays from Sparkfun:
First multicolor seven segments that I have seem. Have to buy me some of them to play with (digikey has them as well).