I would think that you've got a good chance of getting a Jasper by now from most places. As far as I remember they have been in production since the fall of 2008. I bought an arcade from Wal-Mart a couple of months ago and the manufacturing date was sometime in February of this year. As far as knowing what to look for, there is info on the internet that a simple Google search can help you with so for the finer details you should look there. Here is what I remember off the top. The manufacturing date and lot # have something to do with it. Also, there is some sort of power rating number on the Xbox itself, I wanna say 12.1 V, that you can look at before you buy it. You have to look through the little cut out on the back of the box that it's packaged in. Through this little window you can see all of the info that people were using to determine if the console was Jasper.
I decided to get mine from Wally World because I figured that there was a good chance that they would have sold all of their old shit. That and I knew someone who worked there so I got mine for less that $200. You should have no problem finding one, good luck.
I LOVE paying for Xbox Live! I also love that my love for it pisses off so many people.
