As for the meter, it could be on its last legs, or there could be a loose wire.
The easy check for loose wires that you could fix yourself, is to open the bottom plate, and have a look. Anything loose? then re-solder.
Past that I would recomend sending the camera in for a CLA. Many of us here use Eric Hendrickson.
Home
As for the multi-exposure, in the mechanical bodies, I only know of the LX. It is able to index every shot (the manual says to .2mm) so that you can actually rewind back to any frame, take the double exposure, and then forward the film to where you left off. Its a neat feature.
The LX is as tank like as the K1000, but it will cost allot more to CLA. About $220 vs $65.
As for electronic bodies that allow for multiple exposure, I am onlt familiar with teh PZ-1p. It allows you to dial in how many shots you want to layer onto a frame. I don't think it allows the user to role back to any frame like the LX. I would expect other electronic bodies allow multiple exposure. I just don't know which ones.