Just sick of seeing the same two dudes everywhere. I thought there was a mod like this a long time ago but I can't find it.

http://www.gamesas.com/index.php?/topic/1049492-relz-nazox9s-guard-mod/page__hl__NX9%20guard%20mod

There's a mod called http://webpages.charter.net/manauser/morrowind/ by ManaUser. One of the mods it contains, Mixed Guards 2, makes some guards female.

I think the first that did something like this was TheLys' http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=2358. Tarnsman also included the idea in http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=6171, although he expanded TheLys' original 7 faces to 20.