Those are old linear switches. I'd also take the dudes claims that it is a prototype with a grain of salt. The stem does look large enough to use some palstic filler to make them cherry mx compatible, but why bother, most of the caps look like crap.
Link to the ebay listing with more pictures:
http://cgi.ebay.de/ws/eBayISAPI.dll?Vie ... K:MEWAX:IT
ps...guess who asked for that picture XD