If I were you I wouldn't want to spend a fortune on beautiful fabric and then mess it up, and jackets are very ambitious projects as you likely know. If you want to buy something lower end to start off you could try this site:
http://www.fashionfabricsclub.com/catalog_items.aspx?TypId=588
The searchability is awful, but you might find something that will fit the bill if you look hard enough. Living in an urban center, however, I'd imagine that if you look around you would probably be able to find a wholesaler of some sort which is far better because you can actually feel the fabric.
You could also go to tailor shops and see if they have anything they would sell you - it might be a way to get higher end stuff locally. I'm sure there are SF members who live in SF that could direct you much better than I can, so I'll shut up now.
