How about an F16 board or an A cat board? The new L2 design have some really slim boards.

Matt M at Vectorworks,
John P at Stealth Marine (stealthmarine.co.uk),
Hans Klok at Catamaranparts.nl
Marcus Towell at Formlua Catamarans Australia (formulacatamarans.com),
The Lindahls for the L2.