Frankly, I'd just suggest you contact an edge distribution network that specializes in doing this sort of thing such as LimeLight Networks, Akamai, etc etc...
Trying to do it yourself you're probably going to need setup costs of tens to hundreds of thousands of dollars just in servers & load balancers... tens of thousands to millions of dollars in capable routers... and several hundred thousand dollars a month for bandwidth costs.
You're saying that you want to beable to support "up to" 28,000 users at once... and are basing your bandwidth requirements based on that. But, from those numbers you fully expect those 28,000 people to be downloading those files 24 hours a day every day of the month.
The bandwidth capabilities you're asking for is more then many providers here have for their entire network.
Option 2 and 3 will probably need to be distributed, you're best contacting a company which specializes in this type of thing... there's A TON involved in doing it properly. Spending thje type of money involved each month on the advise of a forum post is not a good idea!
Fast Serv Networks, LLC | AS29889 | Fully Managed Cloud, Streaming, Dedicated Servers, Colo by-the-U Since 2003 - Ashburn VA + San Diego CA Datacenters
you cant stream video at 22 kbps, minimum is around 330 kbps for decent quality.
There is minimal improvement between 750 kbps and 1 mbps encoding
What type of hardware will we need to do this? Depends on the quanity of files / storage requirements. We just set up a client for 10 gbps of download streaming per location, in multiple locations using 2U servers with 1333 mhz motherboards, 2 x 2.4 ghz dual core cpus, 16 GB ram, 6 x 300 GB SAS drives in raid 10, and Intel quad GigE nics trunked together to the 10 Gig switch. We figure that each server will do 2.4 gbps, so we cluster 6 of them together to get 10 gbps. Dont need two CPUs-only reason that we did it is so that we can run Xen and use the servers for windows streaming during down times. (1 cpu for linux, 1 cpu for windows)
Should be use just one DC? We have found that it is far better to use multiple data centers, and direct the clients to the closest datacenter using geo ip location. Assuming that your target market is in North America -- the majority of the population is on the east coast, then midwest, then a small portion on the west coast. So would suggest that you set up in NYC or NJ, Ashburn, Chicago, and Los Angeles or San Jose.
someone needs to make a streaming bittorent program to avoid such bandwidth-- Several companies have it now, with mixed results, for downloading streaming.