I began making clip on's as an option for some of my production
findings and have since had several calls for clip on earrings in
custom / one off designs.
If you make earrings with a base large enough for the placement of
an Omega clip or standard clip and hinge, it really isn't difficult
to make clip on earrings from your own designs.
Just "map" the territory needed for the clip placement and choose
designs that will accommodate them. Check for center of gravity and
angle the earring should be worn before soldering the hinge in
Song of the Phoenix