Great roadside fix!
You're leaking engine oil and not clutch fluid, right?
You could be looking at a clutch pushrod seal failure. It's happened on every Honda I've owned that's had a hydraulic clutch. It's no an o-ring. It's a seal about 1.5" around, with a 1/4" hole in the center. The clutch fluid dissolves the seal over time, turning it into Jell-O.
Easy to replace, but like you said, you need new engine case gaskets and a Saturday to do it.
Currently Running Stable:
2010 Honda NT700V
1986 Shadow 700
1986 Honda Trail 110 (Postie Bike)
1987 Honda Rebel 450
1973 Honda Mini Trail 50