Probably the best that I'm aware of is Michael deBethencourt. He's based in MA but does travel. I use his reload method and he has Simunition snub cylinders for force-on-force training, though I don't know if he does that as part of his traveling curriculum.
Claude Werner would also be a good choice, though I don't know if he's still teaching. He's based in GA and has traveled to other locations.
Not snub specific, but Grant Cunningham has a highly regarded defensive revolver program. He's based in OR and travels.
Tom Givens of Rangemaster offers a defensive revolver course, possibly a snub course. He's based in Memphis, TN. I know he does some travel courses, but I don't know if defensive revolver is one that he offers.
TDI in OH has a snubby revolver course, but I'm pretty sure you'd have to go there to take the course.
Dave Spaulding offers a snubby revolver workshop. He does traveling courses, but I don't know if he has a home base.
For the traveling instructors you can see if they have anything scheduled in your area or somewhere you're willing to travel to.
Hope that helps.