You might try the places that do retail canvass work and see if they'll sell you some material. I'm not home right now, so I can't give you specifics, but there are a number of jobbers that supply the retail canvass places, but they mostly only sell to the trade. IMHO your best bet might be to go to an awning shop and ask them if they will sell you the material, at least with an awning shop they won't feel like they are loosing business by selling to you.
Second the idea about an awning shop. My wife also redid my canvas on an old Renken back in the 80s. I got the material from a shop on the north side of Merrick Road in Lynbrook. Have no idea if they are still there.
I have been able to do some canvas stuff with my limited abilities. Yes, it looks less than professional but it didn't cost me $5K when my whole boat is probably worth $4 - $5k.
I went to a place, Ozone Park Canvas on Woodhaven/Cross Bay Boulevard. I am not sure if they are still open.
Zippers, binding, smaller odds and ends I got at this guy [email protected] (?) I am not sure if that's a valid address any more but he sold on eBay and was in New Jersey. The Canvas (Sunbrella Black 60 inch wide) I got from Defender - www.defenderus.com . They are a good shop and I feel bad they are not in Westchester any more.
Dan Ene from Enewhere Custom Canvas told me I could ask him for stuff. I don't have his ## off hand. He is in Brooklyn, Gerritsen Beach.
Something I wish I could find was the vinylized sunbrella for the convertible top. I have drips here and there with the standard Sunbrella after a while.
I used the good clear vinyl for the windows (curtains) from Defender. I never used Strataglass or Eisengard (wait, that's from Lord of the Rings), Eisenglass.
The Sunbrella is very sewable on a home machine. Mine is a 1929 Singer and works fine. The tricky part is when you're going through layers of vinyl and canvas and nylon webbing for support. I also have a hard time with the big pieces and keeping a straight line. Good to have extra hands for support (but no one comes out anyway so why should they help with the work??).