I decided to pull apart an old wallet of mine to see how it was constructed. A full wallet seemed a little daunting so I decided to turn the card holder part into just a card holder as a bit of a pre run to the wallet. I have used goat skin from AAcrack and 0.45 thread from Wuta.
A little more skiving required for a more slender edge.
Nice work! It's amazing how many ways there are to learn this craft to gain knowledge and inspiration.