Can my non-EU spouse employ me?

I am a British citizen and my Australian wife currently lives and works in the UK legally - she is on the first "spousal" visa that lasts 2.5 years. We first applied just after July 2012, so the new rules apply.

Her current visa will expire in Feb 2015 and it is looking likely that I will fall short of the salary threshold and I don't think her salary will count towards this. My question is, could my wife theoretically register a company and pay her wage to me through that company? Thus making her wage count towards my income. Of course the downside is we would have to pay tax again on that money, but that is preferable to her being deported. She would only have to pay me enough to top up my salary.

Would this be legal / possible?

As long as your wife is now legally earning income in the UK - it counts on the financial requirements.

The time it doesn't is when they are earning outside the UK.