i have a nite ize holster as well. its cliped to my maxpedition jumbo with a small brookstone multi tool in it. i think that anything from them will work for what you want. let me know if you want pics of what i have. i have a dare as well and the holster i have works good. i used to wear it on my hip ut since i got the jumbo it has yet to leave it...
cgk are you after a single sheath that would hold both your mt and cell at the same time or one that would fit either so you can rotate between them? Perhaps one of the Gerber tool+bits sheaths would also fit your needs. I'll make a mockup of a Dare when I go home and try if it will fit in one of mine.
Wouldn't you also be interested in a Pock-Its XL?
There really should be a warning when joining MT.org, CAUTION JOINING THIS COMMUNITY WILL COST YOU $$$$$