My husband works for a tint shop part time and his boss has a big plotter that they cut the tint with.. most of the time if they have that machine they do stickers too.. he cut me a big sticker for the sides of my car of my dragon tattoo.. so i would say try your local tint shops or any shops that do car customizing.. like maybe a rim shop, a place that sells body kits, and or remote starts and alarms..
just keep in mind the more detailed the decal the more expensive it usually is gonna be.. be cause the have to weed out the extra vinyl from the design.. so the more intricate the more of a pain in the @$$ it is..
you can also go to
http://decalfx.com/ he has a ton of colors and designs that you can choose from..