I've been unable to buy eggs in supermarkets around my area for about a month now due to the current problems in the industry (ongoing avian flu problem and transition to non-caged birds). The shelves are simply always bare.
Some of the butchers or fruit and veggie shops have them for a higher price, so check those places.
However, I was recently in a country town and discovered there is a plentiful supply, maybe due to the local suppliers from nearby farms or something. So the next time you're on a road trip and passing through a country town, checkout the local supermarket - you might get lucky! I got 3 x dozen packs of 800g eggs for $5.80 which is larger than the 700g I normally buy.
good to know.