On some previous thread I can't find back right now someone joking spoke of UA starting TED service to SYD. I've done some research and it turns out to be technically possible.

All references are to nautical miles.

The A320, according to specs, has a maximim range of 2,900 miles with 150 pax.

The A320 is certified for ETOPS 180 minutes. (I don't know whether or not the UA A320's are certified, but let's just let that go for a moment.)

So - how to get to SYD from ORD on TED:

ORD-SFO - 1,640 miles
SFO-HNL - 2,084 miles
HNL-PPT - 2,373 miles
PPT-AKL - 2,211 miles
AKL-SYD - 1,169 miles

and I'm sure there are other more creative routes, this is the first one I tried. Sort of reminds me of the PanAm clipper, but possible. Ouch!