Say you prefer primes. Doesn't a lens in the 135mm range offer some unique advantages on FF? It's manageable in terms of holding it steady (especially with Pentax's SR), for portraits (or any subject) it isolates from the background better than the more popular 85mm FL, as a walk around lens in public it allows distance from subjects that is more respectful (and revealing) than shorter focal lengths, as the F and FA 135 prove it can be made lightweight and still offer F2.8 (which at that FL is all that's necessary for great bokeh), and it isn't so long that one can't even do landscape shots that are off in the distance.
Here's a link to an article describing the logic of such a FL.
I imagine that without interest expressed by Pentatians for this FL Ricoh won't give us a modern version.