Like Guest:E.D., I have never heard sawmill tuning called Shady Grove tuning. I've never liked "Mountain Minor" as a name for a tuning that is not minor, nor does it make playing in a minor key any easier. Probably "Sus fourth Tuning" would be a more accurate name. As far as "G Modal" goes, calling anything modal makes me wonder, "Which mode?" How can a tuning be modal?

Black Mountain Rag tuning for the fiddle
Spanish Tuning for guitar, named for Spanish Fandango or Spanish Flang Dang.
Jack Campin already mentioned Vastopol or Bastopol tuning, named for the tune Siege Of Sevastopol (sometimes spelled Sebastopol)