Thanks for the comments everyone. I went with North Shore Shark Adventures (the captain was Joe Pavsek). We actually were not in the same boat as the tourists, we took Joe's other boat and we just stayed along side the boats with the cages; the photos above are from two different cages.
The captain (Joe) is a friend of our shark researchers here at HIMB and is proud of announcing that he supports HIMB shark research, so we get all kinds leverage from him. In the end of the month we will take our rebreathers out there to go a little deeper and try to photograph the action better from 10-20ft below.
Pakman: that's a glass "window" in the cage
but yes, they were pretty surprised when we jumped in outside the cage.
Undertow: yes, 17-55 indeed, it's a great lens for shark photography, although I had it at 17 most of the time and was kind of wishing that I had my 10.5mm on.
Rodriguez: I used two Ikelite strobes, but just to barely fill in the dark spots in the sharks. Ideally I should have used a magic filter on those.