Recently I started working on a Qt 5 addon for AccountsService.
AccountsService is a D-Bus service for accessing the list of user
accounts and information attached to those accounts, as its web site
You can learn more about it here.
Qt AccountsService Addon is basically a Qt-style API to use this D-Bus
service and also offers a model that represents users, the API can
also be used from QML.
You can check out the source code from here.
The code works, I'm already using it in several projects but there's no promise of API stability
right now although I haven't made too much changes lately.