Hayes original hydraulic lines are very exxy, about $90AU, thats what I was quoted. I'd look into an aftermarket line and I'd do it over the net from the US. It will be cheaper by far and it's likely to be quicker too. Cant think of a reason you couldn't use the front caliper and disk on the rear of your bike but you will possibly need an adapter to fit the caliper to your frame, you should check this out before you buy.
Good luck.
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Mmmmm...shiney new parts...mmmm