I've had a go at sketching out a remodelled pittodrie which is based on a smaller version of Braga's ground ie just 2 massive stands.
I have had some artistic license and given the dimensions I have are from PDFs and OS Maps scanned off the internet it could be well away from the magical 18-20000 figure.
The problem is the chaos of the whole planning procedure. The number of consultants, private residents and businesses who could and probably would object would kill off the idea before even semi formal drawings could be sketched up.
I also think the actual engineering would blow the budget as the site is so tight plus having 2 open ends so close to the north sea would be a disaster