Anvh: It is very relevant, because all depends on which pro market they want to be. MF was their answer back then, it is their answer now - nothing has changed.
I don't think you were so decisive, but whatever.
Then, know that by going APS-C they would:
a. gain almost nothing in terms of registration distance; I've made an estimation some time ago, when this idea was under discussion but I'll skip that for a more practical experiment.
b. cut the FF path, so if the market conditions would change in such a way that Pentax could and should go FF, they won't be able to unless changing the mount again.
Do the following experiment: take Falk's cut in half K-5 image, and open it in Paint or another image editor. Draw a line over the full length of the mirror. Then, grab the bottom end of the line and, without changing the line's length, drag it until the line is horizontal.
You'll be amazed how little space is left (don't forget the lens would protrude a little bit inside).
This means the only way to actually gain something is to go mirrorless, i.e. OM-G like. Coupled with the proposed usage of the M mount, a rangefinder mount that leaves no room for a mirror... it seems to me you don't know what you're asking for.
"Seconds" is not a word, but the reality - the limits of that technology. Sorry, nobody will plan for some uncertain dramatic technological breakthrough.
No soup, erm, apology for you. You applied Pythagoras to APS-H, not to the ~15.6mm APS-C used by Pentax; you were claiming this is the mirror height (I see now you're calling it length; much better) and that besides it, there's nothing that would need space (everything, including the lens protrusion, could fit in 0,8mm).
Unless you'll put your thought in order and try to better understand things you'll remain unable to claim anything.
Your strawman attempt failed, as expected. I jumped to digital because I had reasons to (and digital APS-C was, even back then, adequate for my needs). Give me the proper reasons and I would adopt a new technology; but don't tell me I should do it just because.
Last edited by Kunzite; 07-09-2012 at 08:43 AM.