I'm looking for a good solution for a custom made strap as well (as I'm sure there are many others that might be looking for ways to use the strap of their choice), so this is an interesting subject...
Don't know if @Gordon has any CAD or model files for you, but from what I understand we're using this hardware, so maybe you could find something for that if you look around (probably not though, but maybe worth a shot).
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I'm looking for a good solution for a custom made strap as well (as I'm sure there are many others that might be looking for ways to use the strap of their choice), so this is an interesting subject...
Don't know if @Gordon has any CAD or model files for you, but from what I understand we're using this hardware, so maybe you could find something for that if you look around (probably not though, but maybe worth a shot).