Designers Eran and Elisa design and manage their company out of Montreal, Canada (..my home and native land!). A cute tidbit: the name "Mackage" was actually inspired by a mispronunciation of the french word for make-up "Maquillage".
Bloomingdales and Revolve Clothing carry some Mackage pieces, but SSENSE definitely carries the widest variety of Mackage coats. Mackage also sells their current collection on their website. My favourites from their Spring 2009 Collection:
Mackage Abby Grape Leather Jacket C$660
Mackage Jules Black Coat C$530
Mackage Jules Birch Coat C$530