Check here for the Kreutz and Leffel videos:
http://www.signilar.com/index.htm
I am unaware of any videos Sherrie McGraw has done, but why don't you write her?
Here's the address I found on-line:
Sherrie McGraw
PO Box 1827
El Prado, NM 87579
505-751-3674
505-751-0144
Although I have not met Sherrie, I have heard from many who have that she is a lovely, delightful person.