Your best bet for something like that is marine upholstery places.
Sorry, can't give you any recommendations since I live in the Near North.
About half way between you and me (if you're in Toronto) is this place:
I've dealt with them for all the fabric and closed cell foam I used in my conversion of a high top van into a camper and they were great to deal with and very reasonable on prices.
If no one here can give you actual recommendations of a job well done, ask there, they can direct you to various places that have been in business for a long time.
If you were anywhere up here, I'd be able to recommend an upholstery shop but she's in North Bay...a little farther than you want or need to go