I was in bunnings today and saw this. Bunnings have the inline version. Around $150 from memory.
http://eco1.digcorp.com/
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( also available online here: http://sunshoweronline.com.au/dig-eco1-solar-powered-controller )
It can also be setup with a rain gauge. They recommend this.
http://www.rainbird.com/landscape/products/controllers/RSD.htm
Has anyone used this or setup a similar system? Any others worth a look?