Andy,
Try this link:
www.toploadertransmissions.com/
I have a Dan Wiliams TopLoader in my West Coast Cobra. Very tough reliable etc. Bought the tranny and shifter as package. Had it delivered to the house (Michigan) from Pennsicola, FL.
If I remember correctly, it was about $1,600 or so delivered. I understand that the TopLoader & 9" rear end is a "bullet proof" combo. Also, the shifter included the "bent" shift arm, boot and chrome trim ring. I had to fabricate a special block/bracket to get the arm in right position.
Good Luck!