It's an old thread, but I used to read the magazine, and it's entirely plausible for preview carts to go missing... http://www.meanmachinesmag.co.uk/forum/showthread.php?t=137
This has been discussed in the past. In fact I'm the reason the post appeared there. The person owning the cart has refused to talk about it further.
forgive me for saying, but it's pretty pathetic that he's hoarding it and refusing to back up the data.
It's tough having something rare. You don't exactly have the money to buy the equipment to dump it all the time, and regardless of what others may think, it feels perfectly normal to me to not want to risk the thing in the mail so it can be sent off to someone who can dump it. Wouldn't want to lose a one of a kind item after all. Besides, I can't remember if I was told this or not, but I think the guy was just playing around and doesn't really own anything.
If they don't want to share it, you may as well assume it doesn't exist and move on. Being stuck on it just feeds the trolls that claim to have something you want but they won't let you have. It doesn't even matter if they have it or not if they aren't going to share anything of it (pictures, video, binary, etc).
Couldn't have said it better myself. I don't get excited anymore for prototypes discovered until I can play it myself.