While looking for a place to buy raw leather online for a project I'm working on, I came across Acorn Bags, an anonymous husband-and-wife team who handmake classic-looking saddlebags for bicycles. While they don't sell raw leather, they do sell hand-cut punched leather straps for DIY'ers; but for those looking for finished product, they've got some good ones to offer as well. Check out their currently-sold-out Medium Saddlebag, up top, with expandable collar; I'm also a fan of their also-freaking-sold-out Roll Bag, below, for spare tubes and tools, and which can be stacked atop other bags.
See the rest of Acorn Bags' lineup here. But be warned if you're doing your Xmas shopping, their site is currently better for inspiration and not commerce--Question #2 on their F.A.Q. list is "Why are you always out of stock?" (Short answer: "It's just the two of us!")