Suggestions for an Australian wine dinner

Matt and Hunt have already offered some excellent advice. You've got a broad range to work with, and a reasonable budget if managed carefully. I'd keep the total budget in mind rather than dividing by number of bottles and seeking an average cost such as $25-bottle. That way you can explore the relationship of various price points to (hopefully) quality.

I'd suggest defining a methodology for your wine selection. By that I mean focusing on creating a situation in which you might explore Australian wine regions in comparison to each other or Australian varietal focus.

So, you might compare a Shiraz from Barossa to McLaren to Yarra, etc. Or, you could look at one major producer (not as much fun as seeking out boutique wineries), such as Penfolds and compare a flight of Shiraz or Cabs at various price points from Penfold. That might depend upon having a very well stocked local source for Oz wines.

Be sure to look at what they are doing with grapes that don't seem to get as much focus in other regions such as Pebreast Verdot and Grenache along with the more prominent Aussie wines such as Cab Sauv, Shiraz and Chardonnay.

And, don't forget some stickies--great sweet white stuff on the front of the dinner and some wonderful "ports" on the back side.

Report back in detail--that is your buttignment.