From what Dr. Kasberg has emailed me (he has emailed me twice so far), it sounds as if there is going to be 25-50 alternates on the waitlist. From what he told me there are 25 alternates right now. On January 15th, they will receive all of their deposits to save a seat (Dr. Kasberg estimated about 20% of out of staters would keep their spot, so about 12-15 people). Next, each of the people on the waitlist are ranked from 1-50 (late January meeting) and then they send out acceptances in early February to however many alternates they think will fill the out of state quota (from what Perfect3435 has told me from last cycle....he was notified in around the 2nd week of February). Each deposit is $500 and they expect many of the out of staters accepted to be accepted to many other schools (just like on the "officially accepted thread") so thats why he guessed about 20% would accept the IU spot.
Dr. Kasberg mentioned they have gone 50 deep in the past, but Perfect said it was less last cycle (I think). It sounds like it could go from 40-50 deep due to high tuition and coast to coast bias (west and east) as well as many of accepted people being from a distance away (ie Utah/Idaho/California) and wanting to stay close to home.
Lastly, I have heard that the list continues beyond February and even until the 1st day of class. A 3rd year at IU who led me around the school and told me about IUSD....he told me he was the last person accepted into IU in his class (pretty highly ranked among his class). Got interviewed in March, waitlisted right away and then got in the first day of class. Point is he was waitlisted in March and got in...its December now...draw your own conclusions.
I would like to add one more thing...and I dont mean to offend anyone...I understand it would be nice to get into many of the schools that you applied to, but if you have 1+ acceptances why are you worrying about being on a waitlist of a school you probably wouldnt even attend??? I think people who have 0 acceptances have a little more to worry about than how many schools they can get into...as I have stated previously my intent isnt to offend, but rather to inform.