Distributed content system with bandwidth balancing

I am looking for a way to distribute files over servers in different physical locations. My main concern is that I have bandwidth limitations on each location, and wish to spread the bandwidth load evenly. Atm. I just have 1:1 copies of the files on all servers, and have the application pick a random server to serve the file as a temp fix...

It's a small video streaming service. I want to spoonfeed the stream to the client with a max bandwidth output, and support seek. At present I use php to limit the network stream, and read the file at a given offset sendt as a get parameter from the player for seek. It's psuedo streaming, but it works.

I have been looking at MogileFS, which would solve the storage part. With MogileFS I can make use of my current php solution as it supports lighttpd and apache (with mod_rewrite or similar). However I don't see how I can apply MogileFS to check for bandwidth % usage?

Any reccomendations for how I can solve this?