Steve -
This is what i was talking about:
https://www.youtube.com/watch?v=JYxDXHGRRrk
Plans here: https://dl.dropboxusercontent.com/u/104241668/BOX%20JOINT%20JIG.pdf
This is another - could easily have an imperial and metric indexer
https://www.youtube.com/watch?v=ZxYL5FU7HU0
Plans here: http://www.ibuildit.ca/Sales/sales-2.html
I think the one you were discussing was:
http://woodgears.ca/box_joint/jig.html