I've also explored agents here in the US and might sign with a big time agency near where I live due to recent doors being opened. I also am presenting the agents with a different concept than most jazz musicians and think that might be why people are listening and not just hanging up on me!
That being said there are so many pluses about agents over self-promotion. I'm willing to work really hard and self-promote (which you'll still have to do when you sign on with an agent!!!) and supplement my agent's big performances with smaller venues. I'll keep you all posted as the process unfolds, but it is extremely exciting!
If you haven't checked out the book "Making Music in Looking Glass Land" I'd advise you to purchase it. It was written in conjunction with the Concerts Artists Guild (major promoters of classical musicians in NYC). It has a lot of "no-nonsense" information in there about agents and self-promotion. I've used it a lot since I got out of grad school.
http://www.amazon.com/exec/obidos/tg...47001?v=glance (search online... I don't think the copy is REALLY $140... I paid 20 bucks for mine).
Hope this rambling makes sense... PM me if you still have any trouble finding the book.