According to Edward Winkleman (
http://edwardwinkleman.blogspot.com/) an artist representative isn't a good idea--at least not as a way of doing business with galleries.
I did a quick search but couldn't find the topic discussing the issue... but Ed's blog is always great for folks interested in the business of art (today posting, e.g., is "Selling Solo vs. Working With a Gallery."
Regarding artist reps... if I remember correctly, Ed said that the last thing gallerists want is another individual involved in the already complicated relationship between an artist & gallery owner. I also got the impression that he thinks using an artist rep can either come across as the artist is too shy (which is a disadvantage to someone trying to sell the artist's art) and/or doesn't know what s/he he's doing & is grasping at straws.