If you're interested, I have a Spark ST6-460NW headlamp I can sell you. It takes 18650 cells, has four "daily" levels (plus one turbo level), mode memory, XM-L T5 neutral white emitter, and clear (not frosted) SCHOTT ultra-clear lens. There is very little run time on this one, less than two recharge cycles worth. The light is virtually new and unblemished. I had intended to use the light on night hikes, but I went with the Fenix HL60R instead (broader beam, making it more useful in the woodland environments I typically hike through). The Spark was used only around the house.
Although it's discontinued, Going Gear has a good description still up on its website, and there are several reviews of the light online (a simple search...all will be revealed).
Send me a note if you want to have a conversation about this.