I must disagree with you on Canberra as a place; I reckon it's a good town, easy to get around, with a good climate (remember, I am from Orange) and lots of things to do.
That being said, will the citizens of the ACT go for a third franchise after the Raiders & Brumbies? Not sure, although we should now be over comparing what happened in the NSL with the HAL.
GCU & NQU are a given, so there is 10 teams.
After that, what teams make the most sense from a NEUTRAL perspective?
Well, with the Bling, the Scum & us in NSW, does it really make sense for a second Sydney team or a team based in the 'Gong? I would suggest that is more practical for a second Victorian team, maybe based at Kardinia Park in Geelong or even Princes Park in Parkville (both obloid, but Melbourne has no large rectangular grounds).
If the FFA goes for a second Mexican team, it CANNOT have anything to do with South or Melbourne Knights, full stop. A Geelong side or a team named "Victoria....." would be much better.
So, let's say that the Mexicans get team 11.
This leaves us with team 12. A HUGE choice here, folks.
Again, trying to think of the game country-wide, we look at Tasmania, NSW or the ACT. Forget WA, SA, NT & Qld.
Option 1: a Tasmanian side based at York Park in Launceston. Forget Bellerive, it will have too many cricket bookings. York Park now hosts regular AFL games, and despite being obloid, does not have a cricket block. Can Tasmania support a professional franchise, given their poor record with previous attempts (the Tassie Devils in the NBL)? Tassie state colours of green & red.
Option 2: a 4th NSW franchise. Where (Wollongong, Penrith Stadium, Parramatta Stadium), will it be supported (Illawarra, YES, others, hopefully), does 4 NSW teams give these teams an advantage with much less travel? Maybe hoops (think Celtic, Parma, QPR) would be an option.
Option 3: ACT. Great, rectangular stadium with a superb surface, wealthy but flaky community, complete focus in summer months (very little cricket played at Manuka). Good ties into southern NSW, especially places like Wagga, Albury and the football hotbed that is Griffith. Raiders colours would be practical, we already have Brumbies colours.
Option 4: I'll throw one more in here. What about a team based out of Lancaster Park in Christchurch, maybe the Canterbury or Southern Orcas (the second of which means a game or two could be played at the House of Pain, aka Carisbrook, Dunedin). The naming of the Phoenix as "Wellington" instead of "NZ" leaves this option open. Christchurch has 300,000 fanatical people, a stadium undergoing massive renovation with a drop-in cricket block, and the opportunity of creating a MASSIVE derby with the 'Nix. This team would play in the traditional Canterbury colours of red and black.
The safest option would be a Victorian side, the riskiest the ACT, the boldest the Tassie side and the "so crazy it JUST might work" option is the South Island NZ team.
Stuff it, I vote for the Mexicans OR the NZ team. We will see.