Yep, I just discovered the same symptoms in my 2000 Jetta, about 203k miles. Took the stone guard off and was just dripping coolant right where the engine and tranny bolt up. The housing where the driver-side axle goes into the transmission is all wet (dealership did replace drive axle seal about a year ago).
It showed up a couple of weeks ago and has been bugging me ever since. Coolant is coming from somewhere, but I can't find it
Top of the engine and tranny are dry. I'm losing about a cup every other day also. Clutch feels stickier, too (but this might be imagined - or something else!)
Connections at EGR cooler, oil cooler, and back behind the temp sensor are all dry. If it stays hot, it's fine. But begins to leak when cooling down (like a seal is contracting and opening up).
I did a red-neck cleaning of my intake manifold and cleaned the tubes of the EGR cooler with solvent, hot water and a wire hanger last summer and I just replaced the thermostat, and the glow plug bridge (to solve a P0380 MIL code). Other than that, it's been just filter changes and timing belts.
Was 2000TDIJetta's resolution a leaking hose above the transmission? If so, I'll just take another crack at it and check the whole length of hoses. Thanks!