All you can do is ask, and if told no, keep calling untill you find one willing to do it. I have had 2 upgraded early, took a few calls to get it done, and be prepared to be told no a few times.
If people are noticing, the phones at verizon are busy now, there are wait times to get a rep, and I noticed that within the last week, phones have went up in price, the razzr and droid 4 for example went up $50, and then they went up another $50 over night one night. The maxx is back up to $299. I think verizon is raising the prices, looking at it this way, if they are going to allow us to upgrade early, they are going to make a extra $100 on the phones.
But in answer to your question, you probably can, but you will have to work at it, and probably have to call a few times, they wont just hand it out, after all verizon wants you off the unlimited data.