CeJay Engineering has introduced a multi-mode version of their FlexLightStick which offers both constant on and strobe in one model.
They’ve also introduced a molded FlexLight helmet mount that can be Velcroed into place. Here you can see it with a finger light.
This is the Helios UAV Beacon. An inch across, it can be wired 9-28v and is offered in white, red, green and IR.