Well in my opinion your pretty limited, there might be something I am missing but here is how I see it.
1) Rent a T1 line and host your own server
2) Contact a web hosting service that offers unlimited space and unlimited bandwidth (hostgator.com) asking them how they feel about this.
3) Break them down into smaller pieces and use rapidshare or megaupload. Although your clients will need to pay for the service or they will get slow downloads and a lot of ads.
4) try services like
http://www.gigasize.com/ which i can not say much about since I never tried them.
Option 4 would be your easiest and cheapest route if it works for you. Only $4 a month.
