Maybe you'll have interest in the RKA line?
http://www.rka-luggage.com/A01%20Products/prod.htmlI have waterproof rubberized bags that came with my CB700S. They are huge and VERY utilitarian. But, they mount very simply like the saddle bags shown in the RKA video. My set from Fieldshear mount the same way, but are far more stylish.
I rescued an old RKA tank bag, as well as an Eclipse and a Lockhart. They all had bad buckles which I repaired with new ones.
Anyway, the RKA is my favorite of the bunch. And all the tank bags have the map feature on top which is great for maps or written directions.
They hold a lot/are expandable and detach via 3 squeeze release buckles.
You might consider these.
I couldn't pass up the newish Fieldsheer saddle bags, and three tank bags for $100.
The stock rear turn sigs on my 550s all interfere with saddle bag mounting. So, I'll have to figure a way to move them back near the tail light that looks descent.
Leather is very durable for wear. It doesn't stand up the the elements very well without a lot of hand nurturing. I've also not seen any leather bags that are water proof, or stay that way without constant care. The ones you've posted about so far will take on water while riding about in rain.
I'm far more about function and utility than looks and style, though. So, maybe none of this interests you.
Cheers,