DeeDee there were discussions about this a while back.

The world record of the largest static gathering of cars of the same brand/manufacturer is held by the fiat 500 club where they had 500 cars in Italy.
UK wise the record is held by Ferrari where they had 385 cars at Silverstone.

I think this will get looked into nearer the time and if interest in the event stays as it is I think we would be able to break these records.

We'll need to get the people from Guinness Book of Records along to validate/witness this before it can be counted