They don't play like this anymore, nor in our lifetimes these bluesmen who survived through to the 60's give us a time machine back to the 20's and 30's and beyond.
Son House
http://www.youtube.com/watch?v=8jN5vqEyV7g
Bukka White
Skip James
John Hurt
http://www.youtube.com/watch?v=BvRxA8gR7bw