Did Apple completely create the design of this type of band? I am not having any luck finding regular 22mm leather loop bands that would work with something like the Click adapter.
I'm somewhat of a watch guy and I've never seen them before until apple presented them. That being said I've read somewhere that some of these bands / design features are very similar to Marc Newson's so you may want to look at that route.
Edited to add link: http://www.cultofmac.com/295250/spot-difference-apple-watchs-stunning-straps-look-just-like-marc-newsons-old-ones/#slide-8
It doesn't appear that the leather loop is a direct copy.