That is the standard offer for new customers only on the Free Dish promotion. The customer pays the $49.99 activation fee along with a $600 upgrade fee, and then gets a $49.99 activation credit on the first bill. You can get this offer from any DISH Network retailer (who can get ahold of a 921).
Your only option if you are an existing (or previous) subscriber is to purchase one for the going price.
It would be nice, but it wouldn't make a whole lot of sense. They can't provide enough for the folks willing to pay full price (or more). Also, if they did, the existing customers would just have another way to beat the system and upgrade for $600 and sell them on ebay for $1500.
I think the existing customer price will stay the same for quite a while. Besides, I don't think that this is a receiver that they are going to want to send out to the masses in large quantities - yet!