One of the benefits of the "Atlantic cousins" relationship, and the Appalachian
treasury of Celtic folk music, is that there is a British remastered version of
"Mountain Gospel" that has some nice versions of early Sacred Harp Recordings.

JSP-7755

There are only 5 Sacred Harp tracks on this 4-CD set, but they are all
remastered in a significantly different way from the versions released in the
United States.

In particular, the tempo tends to be more leisurely, the tenor is warmer, the
alto sounds more like a woman than a baritone singing high & lonesome.

Odem (Roswell Sacred Harp)
I Belong To This Band (Allison's Sacred Harp)
Old Ship Of Zion (Allison's Sacred Harp)
Cuba (Alabama Sacred Harp Singers)
Coronation (Daniels-Deason Sacred Harp)

For a complete track list:

http://www.venerablemusic.com/catalog/TitleDetails.asp?TitleID=9993

(That's not where I got mine, so this is not an endorsement.)

David Olson

However:

I would be very, very wary of a remastering where the
tempo is different than on the original.  If they really were
correcting a somehow mistakenly sped-up tape master, I'd like
to know that they've documented that, & not just used what I
increasingly have to refer to these days as "audioshop" (just so
you'll get the analogy; its not an actual program, but a series
of them, each one creepier than the other, for "correcting" audio
to what the engineers think it *should* be rather than what it
actually was).  Consider how few audio engineers have been acclaimed
singers before you decide that that might be a good thing.

Making the altos "sound more like women instead of high-lonesome
bluegrass high-baritones" would be even more evidence of that
"audioshopping".  Hey!  Some altos *want* to sound like high-lonesome
high-baritones (speaking personally here).