There used to be (hopefully still is) an awesome little place down this tiny mall on Bridge Street:
We just called them "Big Sandwich" and they'd have a long queue every day. My favourites - the ham, or the chicken about 7 years ago
I contend that there is in fact bigger sandwiches than Little Vienna and "Big Sandwich".
It's tucked down an alley, and the queues are long, but the ingredients are fresh and the sandwiches are dangerously large.
I believe the place is called "via Abercrombie", and it's on Abercrombie lane, near Bond st.
http://maps.google.com.au/maps?f=q&source=s_q&hl=en&geocode=&q=via+Abercrombie,+Sydney&sll=-33.906896,150.930176&sspn=5.633709,10.38208&ie=UTF8&hq=via+Abercrombie,&hnear=Sydney+NSW&ll=-33.86377,151.207795&spn=0.011011,0.020278&z=16&iwloc=A almost 7 years ago