I have no idea what these things cost (I'm sure they're expensive though), but if I had a south-facing roof at an appropriate slope I'd consider them.
E.g. [link|http://www.solarserver.de/lexikon/solardachziegel-e.html|here].
Even solar water heaters might be a good option for you and your climate. Who wouldn't like sauna water for "free"? :-)
Cheers,
Scott.