As I posted back in October, our Collegiate Services Coordinator is an ADPi, and our Recruitment & Extension Coordinator - the sorority's first, in fact - is a Pi Phi.
http://www.greekchat.com/gcforums/sh...d.php?t=122841
Our advisors don't have to be members, and some of them are actually (male) fraternity members.
I have no problem with it. I think it promotes Panhellenic/Greek unity and cooperation. Non-members are not permitted to attend ritual events, so that might make things a little more difficult (more so within chapters; probably not so much at national conventions), but I think it's great to get good help from wherever possible.