When the car is cold, it works absolutly perfectly, however after driving it for 1/2 hour or so the disengage point moves closer and closer to the floor until I can't disengage at all. If I let the car sit for a little while (cool down) then the problem goes away (until it warms up again). I've replaced both master and slave cylinders. I haven't checked the crank for play lately, but as of 8 months ago or so it was fine...doesn't seem to happen w/ any of the tell-tale signs of crankwalk (left turns etc)....any ideas?

you might want to check the fork and ball. They might have wear on them. Also check the clutch pedal. Is there air in the system? Also try to replace worn out shift bushings and even upgrade your rubber clutch line to a SS piece. good luck.

I would say bleed that puppy out till your darn sure theres no air in the system. Thats probably the key, big air bubble.