Limit port speed per account

I found a 7-year-old thread that talked about this a bit, but I wanted to see if a better way had come up since then.

I want to prevent all customers from being able to download large files at full port speed. I'd also like to be able to offer unmetered plans at a given speed (10 mbit, etc). I see that mod_bandwidth allows this on a per-vhost basis, but I don't want to manually modify a file each time a new customer gets set up.

Is there a way to set a port speed for a given account? It would be nice to choke large files (first 100 megabytes of a file = user's full port speed, but that speed drops to 1 megabit starting at 101 megabytes), but I'd definitely like to be able to set a maximum per-user or per-plan limit.