I know what you're saying about rotties but I wonder how much combative skill is really gonna be required, I mean feral dogs are pretty wary and most any dog with a surly attitude and a little bit of size is gonna make them keep a good distance. From what I know of feral dogs in qld you're actually pretty lucky to see one, that's even if you're in an area that is crawling with them because they're very cunning when it comes to moving around unseen in rural areas. If you had livestock that would be another story and I'd say a livestock guardian is a good idea, but just as a companion to watch your back and keep them away I think really your options open up substantially and nearly any dog would do the trick.

A bandog is IMO the ultimate personal protector regardless of what it's protecting you from, it's just their nature to bond close to a person and be mindful staying close to you and etc etc. This pretty much applies to breeds like boerboels, bullmastiffs, presas and neo mastiffs and etc as well. And yeah rotties as well but if you don't like rottis don't get one, most important IMO is getting something that interests you that you'll be enthusiastic to take proper care of. Another akita wouldn't be a bad choice, I mean it's just the individual you have now that's over-friendly, that could happen with any breed, chances are if you got another one it probably wouldn't be like that.

Absolutely any dog can be very easily trained to not go after livestock, as long as there is livestock around for you to practice walking them around from a young age. Even working hunting pig dogs are all livestock broken pretty much so I don't think breed really matters in that department. I guess the problem with hunting dogs though is they would be inclined to wander away from you while you fossick for gold so probably better off sticking to lgds or bull/mastiff types (bandogs, boerboels, bullmastiffs etc).

Unless you want to actually nail the feral dogs and take them out, then a staghound/wolfhound or even another bull arab would be ideal. No better defense than a good offense, feral dogs won't stick around in an area where they're actively persecuted.

Good luck anyway, sounds like you're living the dream to me out fossicking for gold in the bush with dogs, lol.