Try Carr's Hobby in Lincoln Park. They seem to have everything.

Just use grommets for everything. ;)

I'm planning on coming up to Duluth from Milwaukee soon -- Milwaukee's was once the tanning capital of the world and still has a reasonably large leather-working presence. If you had any requests, I might be able to bring something up for you.

Marshall Hardware usually carries hard-to-find items.

My friend  is a big purveyor and trader of stone age era craftworks.  He buys, sells and trades bones, stones and leatherwork of all kinds.  I know this isn't exactly what you are looking for but you can look him up HERE, or if that doesn't work email me and I'll get you in touch with him.  It's a fascinating world.  

I don't think anyone has suggested pineapple arts, but they are pretty awesome, too.

Frostriver.com. In fact they contacted me in an effort to increase their sustainability by offering post product material (material scraps) to our nonprofit. 

The potential collaboration could have made a positive economic impact on our organization but unfortunately we are unable to use their material.
Our loss may be your gain.

If you need further contact info, email me.

Alas, Tandy Leather ... I knew thee well.

I picked up a large bag of leather scraps from Duluth Pack Store for $15 and since I am most interested in small projects, they were helpful.  However, they are all the same dark-died brown leather, not tooling pieces.