I am working with a Tenkai palm, (not front
palm) to a back palm pivot and I'm wondering
what the best reference is for this?
(specifically this pivot)

Just use your pinky and pull down into front palm, because you need to get a pinky on the cards for back palm anyway. Unless you wanted to do a modified backpalm without a pinky, sort of a Tenkai backpalm...

How about this, it fits in with a natural move and it's hidden from the front and right of you. "Throw" the card with your right hand to the left side of your body into Tenkai palm. Now, keep your hand palm down and hold it out in front of you. Bring your left hand over and palm the card as you roll up your sleeve to prove it's not there. Turn your now empty right hand over to show it's not in your palm. Pull your sleeve back down and back palm the card. You can then roll up your other sleeve if you wish.

What do you think?

I will work with that idea. It is a sound
solution. I'm still looking for a way to do
it cleaner though. (No sleeves) Thanks for
the help.

This is a multiple step pivot, regardless of the method you use. You need to transfer the cards to different grips at least once. Concentrate on making these regrips invisible and fast.

Here's one of mine (this is all done with the right hand)

Your right side is to audience, the cards are in Tenkai palm.
Middle finger goes on non-index corner. Index finger goes on same corner but on top of stock. Your thumb (which still holds the cards) lifts up and your index pushes down, just enough to allow the index corner to slip between the base of the pinkie and ring fingers (the closer to the knuckle the better) This happens as your hand turns its palm a little to the floor (or else you'd flash over the top) This is the first regrip.

The second regrip positions the cards in a gambler's flat palm. Just extend the index finger (point) Push with the thumb to bend the card. Insert the non-index corner between index and middle fingers at the base (the closer to the knuckle the better) You are now in a deep gambler's flat palm. The third regrip put the cards into euro-edge. Just push the cards into the palm of the hand and let them ride up between the fingers to euro edge grip. All that is left is to perform the second half of a pivot, voila!

Once again the description is a page, but it only takes 2-3 seconds to do. Do not do this move without some misdirection. It can be done invisibly, but with all the regrips it will look suspicous.

Joe DiDonna