Fletcher is currently residing in Azkaban. If he hadn't sold it already (assuming he took it), it's either stashed away somewhere, or the Ministry has it. In either case, I see Harry making a trip to Azkaban to interrogate Fletcher.
Hmm, I hadn't thought about it, but Harry almost has to visit Azkaban in book 7, simply because it's been talked about so much, yet he's never been there (though Sirius, Dumbledore, Hagrid, etc., all have).