one discovery on my latest foray into bluegrass/country gospel is the very excellent marshall family. i don't know much about them, actually, except that they were taken up by ralph stanley in the 70s. ohio, with kentucky origins (?). well the recordings they made in the 70s are remarkable; what's available now is two discs selecting five or six; i would buy them all if i could find them.
judy marshall's singing is somewhere in a transition between dolly and alison krauss; really very pure and seemingly naive and sincere and lovely. her brothers practically whisper their harmonies, and at least one of them sounds like keith whitley (check out the really paradigmatic vocal performance on 'the prettiest flowers,' below); he was probably older than whitley, though, and it shows that this style of country singing goes well back and up into the hills. on the other hand, it just might actually be whitley. the clawhammer banjo and mandolin work also suggest a deep origin, no doubt owing to 'pop' marshall.
one great thing about some forms of gospel music: it is sung completely without ego, in an act of self-abandonment or self-negation. i think this can be amazingly moving, a kind of cure for human self-enclosure. (my other frequently-used examples of this sort of thing are augustus pablo's melodica hymns to jah.) the marshall family really expresses that with great intensity on every cut.
the 'family' as a band is a good american tradition into the early 19th century (hutchinsons, e.g.), especially in gospel. probably the biggest act was the lewis family. an excellent later-blooming version is the cox family, whose cause krauss took up in the early 90s.