If you look at Pentax history for its (Z-serie and later) bodies naming scheme it should look somehow like this:
replacement for K100D -> K200D
replacement for K10D -> K20D
above K10D: K5D
"pro" model: K1D
But the arrival of an hypthetic K5D doesn't mean there'd be K1D. REmeber the model above MZ-5n? Yeah MZ-S... never was there an MZ-1 so...
If they choose to produce only one model above K10D then:
K100D, K10D, K1D or K1000D, K100D, K10D, K1D. Who knows?
In any case, a K20D would a replacement for K10D. But again, Pentax knows probably beter than any other brand how to confuse buyers with stupid naming scheme. No, I'mnot talking about *ist serie which naming has nothing that bad, really.
I'm talking about the following serie (in order) Z10, Z1, Z5 (yes that one existed), Z20, Z50p, Z70. Z1/Z5/Z10 or in good order (feature wise). But Z20 was an upper model than Z10. Z50p and Z70 were sligh variations like ist-DS/DL/DS2/DL2. Talk about understanding market position...