I totally get what your saying but I just find it hard to believe there wouldn't be enough (less asymmetric) thrust to provide movement sufficient enough to allow differential braking to perform some form of taxi... even though it won't be pretty.
With no RW twin or tail dragger experience I have to accept what your saying.
I can't find any material to suggest it will/has taxied on one engine, but I also can't find anything which says it can't or it must be parked on landing, even in authentic pilots notes.
Interesting never the less.