Ah, I realize I missed the original question of the post. Given the number of hosts who are offering 250GB or more of storage, I would guess that the price would increase fairly noticeably if you were to upload 1TB of data today. I'm also guessing that if you moved over 100GB at a time, the price would not increase significantly because people would add more storage to take advantage of the financial opportunity.
I'm more or less making up a number, but off the top of my head it seems reasonable to grow the demand portion of the network by 5-10% per week without dramatically affecting the price. And, even if you do grow the network faster than that, the price should only bump temporarily.
I will advise that the current renting software seems to be buggy enough that I would discourage uploading 1TB of data until we've got the next iteration out. I'm guessing most of your coins would be drained into file contracts that were never utilized. You would get the coins back, but only after 12 weeks. It pains me to ask you to wait, but I do think that's the smartest move. I don't think the software is ready yet.