Joshua Jay has a Bluff Pass bundle where he teaches a multiple shift of four cards and it looks like you're just pushing them into the deck. He also teaches a bluff pass to the bottom as well as on the table. Great buy, I highly recommend it.
I'd go for the multiple diagonal palm shift from Erdnase. Quite difficult, but fits the bill perfectly. Cards are pushed into different locations and as, they're apparently squared in, they're controlled to the bottom, or even to the top with a bit of adaptation.