max levels 60, and no, you can not use any npcs that are not neutral or horde, you will be KoS(kill on sight), and if you do survive a gaurd attack, most everyone will know you are there because of the "location is under attack" messages, meaning you wont live long either way.
EDIT: 1111 woo.
Edited, Mon Nov 15 02:19:12 2004 by VampyreKnight