There’s a DTH for Aeon or perhaps (Quirky?) power strip that is a good example.
You have to create a service manager with a main device (on1, on2, …) and a set of child Device instances. Capability Switch only supports on/off … with no options to specify which sub-switch … so you need individual instances in order to be conforming.
###Update:
Here is the code for the Aeon Powerstrip; but it does not automatically create child Device instances … you have to create Virtual Switches manually.
There may be some newer examples (and LAN related), but this gets the concept across for a start.
https://github.com/notoriousbdg/SmartThings.Aeon-Labs-Smart-Strip
BTW: A good LAN example is probably Philips Hue. It’s Service Manager (“Connect”) SmartApp spawns a device for every lightbulb linked to the Hue Bridge.