I've managed to bag myself a really nice WM-D6C. I paid 180 euro for this one. It comes complete with all accessories, including the original MDR-51 headphones. It's also boxed. The seller said he made a few recordings on it, and then stored it away. So it's basically in new condition, and works perfectly. 

I've been after one for some time, but almost all I have seen on eBay are missing there headphones, so I think I got a good deal. I'll post some picks when I receive it.

Got this one yesterday. Absolutely pristine. All accessories included. Works perfectly. The only thing missing is the cardboard insert which says walkman professional. Hopefully a box might come up for sale on eBay with this cardboard insert. I'm a very fussy collector!