Welcome to the Yard, and congrats on your first score. SOD is one of my favorite.
Something with that type of versatility, I would say go with kydex and talk to the maker and explain what you need. You could probably got with a snap on dangler style leather sheath that will attach on your belt and molle strap with a support tie-down/loop at the bottom. I'm not sure what his turn around time is at the moment, but if you want something special, talk to Jeff (rainwalkercreations.com), he'll do leather or kydex. Chance are he probably has a SOD and won't need you to ship it to him.
A cheap alternative is to track down those condura sheaths, they can attack to the belt via the loop, or attach to molle packs via the strap running down the back. They sell them in 2 sizes here at the store,
http://shop.scrapyardknives.com/category.sc?categoryId=5 I remember some saying the 6" version could fit with a small modification.