I imagine the biggest difficulty would be that the funnel would have to be able to turn with the windmill to point into the ever-changing wind. Also, in very high winds, the large blades can be 'feathered', that is, made more-paralell with the shaft, to keep them from being damaged. I can imagine your funnel would have to have a mechanism to allow large winds to blow through them to prevent damage. Not a bad idea, just complex.

In Perth they have 25 to 40 knot seabreezes every afternoon(best place in the world for kitesurfing) The cold antartic water moves up the coast combined with the hot desert(you know the rest). If the setup of the funnels was at around 90 deg. it could catch 90 deg of seabreeze action.

Just another quick idea. I wonder if you could use gearing to compensate for higher wind/lower wind or will a generator work efficiently at any speed?

This has been done, although the funnel is behind the turbine and "sucks" more air throuhg. It does increase power output but is too expensive to attach onto the turbine. Remember that all wind turbines are on top of tall towers and any weight and wind resistance you add means building the whole structure stronger, heavier and more expensive. Imagine the funnel in a storm - it would need to be incredibly strong to survive. So it's not viable. There was a company that proposed this a few years ago - it was a scam. They took investors money and then closed down.