We can handle what you describe, but if the video file is larger than 500MB, you'd need to subscribe to our $18/mo plan and store the video file on your own server instead of uploading the file to ours. The download links we issue to each buyer would still work the same way and would also cloak the remote origin of any files we deliver from your server through our service.
Another thing to consider is how long it would take for typical buyers to download a large file; any download is only as fast as the slowest link, which is almost always the downloader's own connection to their ISP. This calculator will estimate download times for various file sizes across various connection speeds (residential broadband offerings typically range from 256kbps to 1.5Mbps):
There you can see that a 500MB file would take nearly an hour to download at best (and probably longer in real-world conditions) with a 1.5Mbps DSL connection, and several hours over a 256kbps DSL connection. Cable providers advertise speeds ranging "up to" 6Mbps, which may be theoretically possible, but I've rarely seen much better than 1Mbps or so with such connections personally.
As another alternative, you could consider embedding the video in a secret page on your site, and then use our Redirection feature to send buyers to that page after payment:
For yet another alternative, you could use our built-in SwiftCD integration to have them duplicate your files on a CD/DVD and mail that to buyers on-demand automatically whenever an order comes in:
You could even combine the SwiftCD option with a PDF download, so buyers could get that download right away while waiting to receive their disc with the video in the mail.