How do I find a drywall specialist subcontractor?

I do most of my reno work, and hire subs when i need them. What I need is the kind of guys that ONLY do drywall, not a GC who also does drywall. I have a unit that needs 1/4 drywall over many cracked plaster walls and ceilings, and as I've heard it, the specialists would be able to do it far faster and cheaper than the general guys because that's ALL they do, and they have the taping machines and skills to make it fly. Any pointers?