This sheath was just released today by Hedgehog Leatherworks. While not ultralight, its a new redesign of the HL Blackbird SK-5 Sheath. I've used the Blackbird SK-5 for the past few months and has become one of my favorite production field knives. I've had the sheath for a few weeks and it definitely compliments the SK-5.
All the Hedgehog sheaths are of extremely high quality. This new design features a pocket and ferro rod. It basically becomes its own survival system. It is expensive, but it comes with a 25 year hard use warranty. I did have to take some heat from the wife- she just doesn't understand the importance of gear...lol.
I've got a full review on my website if you guys are interested
Anyhow I just wanted to share with you guys....have fun