I had a problem similar to this on my old 1g N/T. The shaft actually had a groove in it from the throwout bearing riding on it wierd, which was keeping the clutch from being able to enagage completely. I'd look at the shaft really well and see if there is a ridge to it at all.
If that turns out to be the problem, look into shaft sleeves. They are really cheap, but unfortunately I couldn't find anyone that makes them for a 1g.
