I woke up this morning with a premonition that my order had finally shipped. I stumbled into the computer room and checked the product status. It still claimed "Not Yet Released" but I noticed that there was now a rebate available. I checked the terms and noticed that my original order wouldn't be eligible for the rebate but a new order would. The new order would cost a little more up front because amazon had decided that the iMac wasn't actually eligible for amazon prime shipping but the rebate would more than make up for it. I decided to figure out the exact cost later today and cancel and replace my order.
A little bit later I checked the product status again and noticed that it had finally changed to "Usually Ships In 24 Hours". I went ahead and cancelled the old order and placed a new order that should be eligible for the rebate. I chose slower shipping (I've been willing to wait a couple weeks to save a couple hundred dollars, I'm not going to pay another fifty dollars to get it a couple days sooner) so I should finally get it next week.
It's just about four years to the day since I ordered my last desktop computer. The rebate means that even with the extra memory i ordered recently the entire purchase fits within the money I made selling off half of my Apple stock (just before their recent split).