Here are some photos of the pendant.
I didn't have a project box that small so I just cut up the Adafruit box and hot glue gunned it up. I had some window tinting laying around to darken the unlit LEDs. The frame and other stuff was just in my junk bins.
This is using a lithium Ion battery attached to a charging board. The switch on the side lets you turn it on or off and the button is attached to the reset on the Trinket. I made sure to cut a slot so I can access the mini USB on the Trinket to reprogram it.