Just came across this website which is part of House of Tartan:

"Attending a Scottish wedding this weekend? Best man speech written but still no kilt? Ceilidh or Burns Supper coming up, but no suitable attire?

Welcome to Lastminutekilts.com, the site which enables you to purchase your traditional hand-pleated tartan kilt for delivery to most destinations in three working days."

http://lastminutekilts.com/

The sizes available appear pretty limited, but it might help someone in a pinch one day.

Best regards,

Jake