Some of the problems that can happen are timeouts, disconnections, and not being able to resume a file and having to start from the beginning. Assuming these files are up to around 5gigs in size, what is the best solution for dealing with this problem?

I'm using a Drupal 6 install for the website.

Some of my constraints due to the server setup I have to deal with:

1. Shared hosting with max 200 connections at a time (unlimited disk space)
2. Shared hosting.
3. Unable to create users through an API (so can't automatically generate ftp accounts)

I do have the ability to run cron-type scripts via a Drupal module.

My initial thought was to create ftp users based off of Drupal accounts and requiring them to download an ftp client for their OS of choice. But the lack of API to auto-create ftp accounts and the inability to do it from command line kind of hinder that solution. If there's a workaround someone can think of, let me know!

Thanks