This prototype was based on the
MZ-S, the similarities are obvious, the high end camera in the MZ film SLR generation.
Story goes that Pentax never put this in production because the Philips sensor was too noisy and they abandonded the project in 2001.
Contax used the same sensor for their first DSLR, the Contax N Digital, the first full frame DSLR in 2002, which was produced for only one year. The noise level was too high to be usefull already above 100 ISO, and it was major cause of the the death of Contax in 2005.
Pentax instead came out with their last film camera in 2003, the *ist, together with their first digital, the *istD, which used a cropped sensor. Since then they have got more dedicated to the APS-C format in their lens program than any other brand.