Since you mentioned leather alternatives - something natural that weathers well is cork leather! I thought it was bogus but it looks awesome, it supple and sturdy, easy to work with, water repellent and natural :)
It was seeing your articles on Fabrics-Store.com that made me want to give their linen a try, and I have been very pleased. You guys and your work are an inspiration for me, thanks for sharing both your results, and some of your process!