Yes -- I think that the MX is the only M body with DOF.

The AFA 1.7X does "take control" of AF functioning (so that the actual lens, even if it's an AF lens, is really being used as an MF lens). In fact, one of the neat things the 1.7X does is to limit the focusing range with AF lenses that have long focus throws, so that they can "hunt" less (assuming the light is bright enough to compensate for the TC's "darkening").

I have no experience using the AFA 1.7X on that particular lens, but my experience is that, in general, TC's (including the AFA 1.7X) don't work very well with most zooms, but do often work reasonably well with many primes (where they are always a compromise, of course).

I don't know if this post was the one referred to, but I really like this setup:

"Perfect focus everytime"

I like to call it "Squeeze Focus"... It works wonderfully with the K-3 because of the perfect location of the AF button.

LX 4EVR !!!

This is just another "me too" vote for the LX. For an old cam, it is still a superb photographic instrument. The "sticky mirror syndrome" can be a bit of a "sticky wicket", too be sure, but that is its only really common flaw (and easily fixed with a CLA, which most any old cam needs every once in a while anyway). [I am not saying that nothing else can go wrong with an LX, but "sticky mirror" is more commonly seen than anything else.]

Yes indeed. The MEF is sort of like a "Super 'ME Super'" -- it has the same controls, plus some additional ones that allow for "primitive AF" with one lens, the AF 35-70/2.8. However, with any other MF lens (K, M, A) (or even with AF lenses focused manually), the AF circuitry can be used for "focus confirmation", which is (methinks) a bit of fun to use (and sometimes it's even downright useful). Furthermore, since the MEF was released some time after the ME Super was first released, used MEF copies are ,on the average, not always as old. Plus, unlike with the ubiquitous ME Super, you'd be using a piece of genuine photographic history.

My two favorite film Pentax bodies are the MEF and the LX, and, as others have suggested, since the LX is not unlike the A1, that might make for a good transition to Pentax, too...

I'm surprised at just how many pix show "the boys" with Pentax cams . . .

"the Google"