There's a number of people attacking Dick regarding his comments, go back and have a reread, because it seems you don't remember from one sentence to the next. He said that he has a secondary attitude indicator that has a battery backup and that he carries a Garmin 296.
Now there are a number of different secondary attitude indicators, but there's certainly self contained attitude indicators with internal backup battery that continue running when "the ship's battery has gone and everything else is up **** creek" available on the market. Hell it was mentioned similar models are available on the 400ER and without Dick being back on the forums to reply, I think we could give him the benefit of the doubt on what he meant even if it didn't read clearly.
So with that and a Garmin 296, I'd say you have enough navigation and attitude information to get to the nearest base. I can't see the 296 being approved for sole means navigation or even primary means, but hell I'd take the option of a 296 and a standby attitude indicator over a black cockpit.
There also seems to be a hell of a lot of anger in this forum which I think is misdirected passion for wanting to improve things - pay rises are nice (and I'll happily take one tomorrow), but quite often a job you can be proud of means so much more.
You guys have stumbled across a failure mode which could result in a hull loss, and a lot of suggestions on which bits of swiss cheese to change. Where I work we would get our arses kicked if we left that situation untouched. There is a change management process, and peer review to make sure we're not going from bad to worse, but anyone who left something so significant without doing anything about it, would more than likely be asked not to come Monday.
Now, if management isn't taking these problems as seriously as they should be, then that is an issue CASA should be addressing and you have means of contacting the regulator to ensure that happens.
If CASA is sufficiently ineffective to help you in your cause, then I'd suggest its time to start taking it up with your local politician. There's more than enough of you Australia wide to make a heck of a lot of noise and get some action. Inaction on your part because "I can't change it" is just laziness.