Try Marlo's "Streamlined 21 Card Trick" (The Cardician p. 134), or, in my opinion one of the best, Marlo's "Nouveau 21 Card Trick" in Marlo Without Tears, p, 146. The intro to that description (by Jon Racherbaumer) mentions others.
I sometimes do a tongue-in-cheek version, with a memorized deck: I have the deck cut, and then deal out the standard 3-overlapping-row layout BUT ALL FACE DOWN! I do this obliviously, as though I don't realize that I'm making a mistake. I ask the spectator to think of one (which gets a laugh, because none of the faces are visible). So, I ask him to point to any one that he'd like to think of. He does, as I turn around and ask him to just peek at the one he chose. He does and remembers it, leaving it in its position. (At this point I already know his exact card, because of the stack and some very simple counting/addition to where he pointed.)
I can now reveal it in any way I like. In keeping with the original premise, I then turn back to face him, gather up the rows, and then redeal them AGAIN FACE DOWN. I ask him which row his card is in, and of course he can't tell because no faces are showing. So I ask him to point to ANY row, and then ANY card in that row. He does, and I then privately lift up the corner of that card, so that only I can peek at its identity. I look at him and ask, "Oh, the Six of Clubs?" (miscalling it and actually naming the correct card). The spectator is stunned, that he apparently found his own card, face down. Meanwhile I gather the 21 cards up. (If you want to go into this version deeper, there are actually math calculations that will tell you where the real card is in this second deal, so you can really locate it, but it's not necessary).
At any rate, all of these versions do what I hope is your intention: they stop the spectator from wanting to show you any more of "his" great magic.