Alex wrote:but once you go so far with the pressures you will have trouble with even tyre wear
You are more likely to increase wear due to a lack of pressure. I believe that anything up to 48psi on most tyres is safe and wont result in increased wear in the centre of the tyre.
I have my turanza's @ 40psi at the moment, it feels a touch too high. I found 38psi front 36 rear to felt the best. And I am wearing the shoulders slightly more than the centres, but I think this is due to the alignment specs.