Great idea. Here's a first attempt, to get the ball rolling. At the beginning, the extra cards are in a Gambler's-Cop-ish position, concealed under the fan, and the handling is somewhat contrived. This is covered by the patter ("how amusing
it is... to watch the average player inspect his hand"). I'd put those cards in a full Gambler's Cop so I can handle the visible cards more freely, i.e. passing them from one hand to the other.
Split the fan for a moment to loosely show 3 cards in the right hand and 2 in the left. These 2 cards afford some cover so you may tilt the hand forward to show them, if necessary. Pull out the Ace and the 10, lay them on the table face down, and have them guess "to make sure they're paying close attention".
Now for the Monte part, as you explain they have to try and pick a card that is not a 10, openly reverse the order of the 4 visible cards as you display them, peeling them into the right hand. Without even squaring the cards, casually one-hand fan them to the right so the 10 is left injogged. Close the fan against the left-thumb crotch and obtain a break under the top three cards, letting the injogged 10 coalesce with the hidden packet.
Without pausing, turn the packet end for end towards you, performing Marlo's Pivot Switchout (a wonderful sleight from "35 Years Later", see also "The Card Magic of Edward Marlo", p. 17). This leaves the picture cards in a full left-hand palm and the Tens in a face-down packet, in view. Spread those cards immediately and toss them, still spread, to the table. This gives you a chance of disposing of the picture cards in a convenient place, as Hofzinser used to say, while a card out of the four is being picked.
One more thing: When you first put the Ace and the 10 on the table, you can say: "Look, I'm gonna shuffle them with just one finger." Do so by stretching out your right hand, as if not wanting to get close, and shift the cards around a bit. This conditions the spectator so that later, when you lay the Tens on the table, you can do the same and easily pocket the palmed cards.
[ August 08, 2001: Message edited by: Rafael Benatar ]