Inspired by the @philipjury design hack post, I'm sharing an idea here for feedback. I'd been pondering ways to give a finished look to the back of leather goods, including straps, without lining them. I had some 50% water-50% Uniters matte black edge paint in a little squeeze bottle. So I applied a couple of thin coats on the back of some English bridle from Wickett and Craig. Turns out to be a really interesting finish that seems like it might be durable. It's not a finish for luxury items, but it gives a medium satin finish, not slick but not at all rubbery-tacky, as I thought it might be. It's easy to apply, dries fairly quickly and does not appear to need any polishing, etc. The photo shows the back of a piece of bridle on the left alongside a finished piece. I've got a toiletries bag that I like to make, and I believe I'll try this as an interior finish, rather than leather, cloth, plastic or whatever. Thoughts?

@smithdal That's interesting! I like the idea. I think if I were to go this route I would try using Fiebing's Acrylic Resolene, they have it in some basic colours.
I wonder if Angelus paints would work too.
Have you tried slicking the flesh side and dyeing it?