I once figured out that you can play all the way up an A major scale in all harmonics in one octave...
e---------------------------<12>----------------------------
B--------<12>-------------------<7>---------------------
G--------------------<7>-----------------------------------
D--<7>----------------------------------------------------
A--<5>--------<9>----------------------------------------
E-----------------------------------------<9>---< this one is an octave too low
You can find a leading tone in the correct octave *slightly* ahead of the sixth fret, but somewhat difficult to hit. Also, the octave is on the A string a little in front of the second fret.
Also for creative uses of harmonics, i recommend listening to Jaco's Portrait of Tracy.
http://www.youtube.com/watch?v=nBBG_2tPiOU