I had a problem similar to this and it was my clutch pedal backet. I had no leaks anywhere in the clutch's hydrolic system. When the bracing on the clutch pedal bracket fails, it feels like you get resistance somewhere but its just the metal bending.

I had to pull my bracket out (big awckward thing under the dash) bend it back to normal and weld it back up/brace it.
that hole on the left is where the clutch master cylinder comes through the firewall  

That might be yer problem.

I ended up replacing the master and slave cylinders before I figured that out.