Thanks!
Here is a picture to show that the A6 1997 clutch cylinder is useless. Its too long to fit the clutch pedal and not foul the brake booster. A8 clutch cylinder should be ok, I cant be bothered to buy a metal audi A4 cylinder (which feeds the slave cylinder hose on the outside of the footwell)
If you're going for a 8mm thick pedal like me, just get the 1997 A6 clevis and pin from Audi.
I wonder how much it would cost to get a custom titanium clutch pedal made, perhaps by these guys?
http://www.force-racing.co.uk/front-suspension/