Adam, another option to consider is Costco.
Here are the coordinates of the one local to you:
http://www.priceviewer.com/costco_locations/431-Arizona.html
I don't know if there are variations in Costco policy from state to state, but here they extend warranties for free to two years.
What happens when the TV fails during these two years? You bring it in, and trade it for one of equal value (or maybe even upgrade). I am not 100% sure that this is the actual policy, but this is what happens 100% of the time here. I've seen it with my own eyes. Incredible. No need to send it in, wait time, shipping costs, etc. Get a newer, and therefore better, TV.
However, the actual inventory in the store is usually limited (as are most electronics choices), and they will change rather frequently I think.
You can order directly from their website. The 58" 800u is $2000 with shipping included, and yep, that free warranty. I don't know if they handle on-line warranty any differently.
Ok, yeah, you'll need a membership. But if you have any family or friends that are a member, maybe you can convince them to accompany you, or help facilitate the on-line purchase.
The 58" gives you 35% more display size than a 50". The cost differential between this and the display you bought, if I got the right number, is 40%. So yes there is a slight diminishing return there, but remember that 2 yr warranty, and then consider that the larger sizes usually have much greater price points, for whatever reason, be it economies of scale, luxury item, or whatever. Just a month ago I thought 2.5k was a great deal, but now at 2k, I think this is the best deal going for anyone who sits more than 6ft away from their TV. JMO.
**When people ask me for my "expertise" in buying a new TV, my advice is always the same: "Get the best plasma you can at Costco".
I have a close friend who has worked at Panasonic for over a decade. I actually know his employee login and password for their pricing!! He asked ME, yes a Pana employee, in helping to shop for a BR tv. The difference in price at Costco was less than $10 more than his employee pricing, and I definitely told him to get it at Costco, even as an employee of the brand. He completely agreed and has since done so.
This is the rep Costco has where I live.
This comes from an Amazon fan as well, as you know.