Pere, thanks, Tric seems like it might be the "trick". If I understand correctly, the Tric unit fires a speedlight attached to its hot shoe. In principle it should also fire a PocketWizard, for example a Plus II unit. The unit also has a PC port, so it should work. It seems from the FCC notice in the manual, that connectivity between iPhone and Tric is via Bluetooth.

This is what I am looking for. Now to find time to dabble with it!