Also try The Multimedia Directory , published by The Carronade Group. These people are easy to get on the phone. I once just called a company and ended up doing two titles with them. My experience has been all over the board. And you have to get interactivity.
Character is spice in the interactive dish, it enriches the main course.
But in a sense, your most important character is the Player or Websurfer. You have to keep him or her involved, satisfied, rewarded and challenged. You'll need to convince the TechnoDudes that you can do it better than they can. One way to meet that challenge is with your writing samples. They were ideal for the job.