I'd like to find a vertical leather case that fix the phone, with or without a skin/case on it. I'm betting the leather holster from Seidio will fit, I have on very similar that it'd fit in fine, but it's horizontal, and those just don't work for me it seems. I'll definitely be keeping an eye on this thread, especially if anybody finds a good vertical case...
I'd say 99% of the leather cases that say they fit on places like ebay are generic and not designed to actually fit our phones. That, and most of those cheap Chinese cases aren't well made and break very easily, especially the belt-clips (broke 2 cheap blackberry cases I got from ebay shortly after getting them, one, within a friggin hour, bought a real RIM case, and I've had it through 2 phones and never had a problem).