Amazon.com (US) has Richard Chase' book American Folk Tales and Songs which has several songs written in Shape Note format.         
        
American Folk Tales and Songs by Richard Chase (Paperback - Jun 1, 1971)
Buy new: $9.95   In Stock
Used & new from $0.01

Richard's original book is long out of print, but Dover Publishig has chosen to include it in their catalog of reprints.

Shape Note is merely a means of writing music so that people without an instrument to pitch a song, or who can't read music, can sight read music with no other aids. The seven notes of the scale are written on a standard staff, each with a unique shape that tells the singer what the note should be. One illustration of Shape Note notation can be found here, and this site discusses Sacred Harp Singing.   

That having been said, much Shape Note singing often consists of the older hymns from the Southern Appalachian Mountain area, so the content rather than the means of writing the music may have created the effects you liked so much.

Dave