Robin,
Is she currently in a band? If so, it could be the band holding her back by not wanting to get more exposure by sending out promo-kits and trying to get booked at festivals around the country. If she's on her own, maybe she should start a band and do the above.
I like the idea of your world-wide search website but practically, unless a band has plenty of money behind it, band members probably wouldn't want to do a nation wide search for the perfect member. Hard to convince someone to move for a band that can't promise much.
It seems like most people who are "discovered" have been at it for awhile doing all the hard work to get them to a spot where they can be seen. They've played the hole in the walls and after a while move on to better venues. You have to be hungry enough to go for this, not just good enough.
This is all off the top of my head and I don't pretend to know about this business. Good luck to your friend. I'll be interested to read what others think.
Emily