The definitive list (thanks for the help @moon shot @Arti, @Seth & @vsbabolat ):
Current users are denoted by green text
Mats Wilander: 16x18
Juan Martin Del Potro: 18x20 - 2009 US Open Singles
Marin Cilic: 16x18
Todd Woodbridge: 18x20
Mark Woodforde: 12x16 (only player to use this pattern)
Daniel Nestor: 18x20
2002 Aussie Open Doubles
07/10/11/12 French Open...
Pro's (Past and Present) That Have Swung a Wilson 6.1 [Includes major winners]
Current users are denoted by green text
Mats Wilander: 16x18
Juan Martin Del Potro: 18x20 - 2009 US Open Singles
Marin Cilic: 16x18
Todd Woodbridge: 18x20
Mark Woodforde: 12x16 (only player to use this pattern)
Daniel Nestor: 18x20
2002 Aussie Open Doubles
07/10/11/12 French Open...
Pro's (Past and Present) That Have Swung a Wilson 6.1 [Includes major winners]