Any reputable car audio shop would be able to do one for you. I would try and go to a specialist car audio place that only does car audio. I would stay away from Strathfield, Autobarn, JB HiFi etc. Although these places would be able to make one for you I just think a specialist store would do a better job. Although there are a few of those stores mentioned above with decent installers.
Maybe post what state/suburb you live in and someone will be able to tell you a few reputable shops near you.