I know Elishewitz (sp?) made a clip sheath designed to be worn in a pocket to carry a clipless knife. Should work just as well IWB. There were 2 sizes, the larger of which should fit a Buck 110. Those were nylon w/plastic clip, though.
I know William Henry made leather clip sheaths with metal clips for his knives, but I don't know if any are big enough for a 110. Most of the WH knives I've seen were quite a bit smaller.
Hopefully someone will come along who has more info than I do.