Pentax is carving out a nice niche as the rugged-all-weather-outdoor-sporty photography brand.
I'm not sure they are focused (or should be) on the magical "full frame" that so many people think is necessary. Just look at their lens lineup! I think they have released only one "new" ff lens in the modern era (the 100mm WR macro).
Their new Limited DA lenses are really nice metal and compact. But are for APS-C... and have no AF motor. Like old Nikon lenses I believe they rely on a screw motor from the camera body. They are accurate, but loud and the focus ring spins powerfully while you are focusing. I guess that is part of the reason they can stay small. And no IS, which is in body. They are not cheap.
They also have some other top end all-weather DA* lenses that are also APS-C, and expensive.
The cool thing is that they take all the legacy K, M, A, etc. lenses beautifully!
I actually bought a Pentax K-01 as a fool around camera and it is AWESOME. The focus peaking on the old manual lenses makes it lots of fun to shoot those great old lenses!