Please check out my work. I have worked for a variety of clients including Zenescope, Scholastic, and Bakugan. I also have some experience in t-shirt design.
How stuck are you in having the person be somebody who's worked with big companies? There's a few of them here but I'd assume they are all staying pretty busy.
There's plenty of other artists though that are as good if not far better than the people working for big companies.
What exactly are you looking for in the way of art? What's the pay? What's the time frame your trying to work in?
What difference does it make? Seriously, if you want Jim Lee to draw your shirt design for you, contact HIM. Or Bolland, or Kubert, or whoever else. Try looking for an illustrator, rather than wait for an illustrator to contact you. DA is not known for having big name illustrators browsing around the job forum. They already have their hands full. You're not going to get someone big like that unless you have a huge budget.
That Jim Lee thing was a joke..... Anyways if I really wanted Jim to do a drawing for me I could taken a train to the next comic con and ask him in person...Anyways I was hoping for someone who had some previous experience. Perhaps someone in a big company.
Jim Lee you out there? :-P