Interested in this too, as I've thought off an on about buying a lower end MTB (used or new) and converting to drop bars. I'd probably go full rigid, but suspension fork with lockout would be OK too. Basically I'd like something akin to a poor man's Fargo.
My research on doing a conversion gets me to believe it might be easier to forego the drop bars and try an alt MTB bar like the Jones loop bar, velo orange crazy bar, or something similar. Otherwise, you end up buying too many parts, not to mention the geometry of a MTB with drops gets you too stretched out.