I've bought sheets from cameraleather.com, and on two occasions, I had to send him reminder e-mails. I eventually got what I wanted, but the wait sometimes was too long.
Others have had similar experiences -- if you go by Internet forum postings.
I have some of the stuff from Micro-Tools. My only complaint is that it has very tiny holes in a grid pattern -- I can only describe them as breather holes. And of course, there is no adhesive.
I like the fine-grain stuff from cameraleather.com. I also have some of the large-grain pattern. I just reskinned my Komaflex S with the large-grain material. The original light-green rubber stuff was falling off in huge chunks. I had bought this leather for a National Graflex Series II. Now I'll have to buy another sheet. Damn.
If I had it in another color, I probably would do it again. Maybe red? Hmmm.
