For my Fujifilm X cameras I have designed a shoulder strap, which does not take up much space when the camera should be packed Down, and does not weigh much but still is more than strong enough.
The strap is designed on the principle that it should be as simple as possible. For the same reason I make it only in fixed lengths without the possibility of regulation. (How often do You regulate a strap?)
The shoulder strap can be supplied with keychain, carabin lock, or triangular split ring. And you can choose from a strap with ventilation holes or without holes. I call it ventilation holes. In fact, it is mostly a matter of appearance :-)