i've been with comcast since they transitioned from @home. until recently i started uploading more than the usual.. is there a cap on the upstream as well?
If you need to use that much bw you are better of getting a server somewhere and connecting remotely to it. Sure you have to pay a bit for it but the prices are cheaper than losing your connection for abuse.
It cuts out the middle man "Comcast" and you will have much better speed (100mbit) with as much bw as you need if you so choose.
