The one that mysteriously vanished completely, while I was dissambling it. Together with a few hundred metal ingots and some other small stuff (which I had not even realized was lost), all picked up at the same morning, put into my inventory and... suddenly had not been there any more.
It all had gone into 3 very, very old bags in the moving box that was part of my inventory at that moment. Client support told me that other people had experienced similar problems, so my advice would be: Check out all those old bags which you know are empty and which you have no use for anymore.
Your stuff might be in there.
Of course, however it glitched into there, is a mystery. ;)