I would pick that K-1 with love! Actually if i pick another camera, it would be a Pentax too, and my current K-x would be for my girlfriend, who i picked a trashed EOS300 and almost fully restored it to a working condition. Hell, i even recovered the lithium battery from a 0.00v condition, and while it doesn't last like brand new, it withstands a 12h car shooting season without much trouble. The biggest trouble is a dead lens that i picked and unfortunately, the aperture mechanism is somewhat dead, i guess it's the ribbon cable that runs inside, but i'm not that friendly with dismantling a lens. Also if both have pentax, it's just a matter of sharing lenses and keep going.
Actually, the FPS performance on my K-x improved at around 0.5 FPS i'd say, i remember the camera with AA's being able to save a photo from time to time, now it's just impossible, the buffer is the same speed but the FPS speed and focus speed improved a lot since i could bump the non load voltage to 6.2 volts (6.1v at load) from that hideously unstable ~5 volts that usually fed the camera for 5 shots before its die
so i guess i improved the camera on many areas with only a power plant upgrade. It's just working like it was on an original 80€ AC-DC adaptor, it gives a green indicator (even when the real batteries are dying and starts doing weird things like random corruptions at a random shutdown) but i guess you can't have it all together on a DIY. Just for lulz, i have to look the charge level with a multimeter, but i know i can do 3 exits without charging it, that's pretty much around 1800 shots and there's around a 20% battery left so it can still be going but risking a lot i don't need too. Also i can attach a powerbank on the usb port so it doesn't matter, which camera can do that? I'm sure even the most expensive ones doesn't consider that
BTW i'm confident that the K-1 is much more better designed and doesn't have that kind of problems