Other Mamet movies that have a similar feel are House of Games and Homicide. There are other con artist movies, but none have have that Mamet stamp on them.
And don't forget another Mamet film, Heist. You might also like Out of the Past, Chinatown, The Big Sleep, The Maltese Falcon, Double Indemnity, Red Rock West, Detour, Blood Simple, Rififi, Le Cercle Rouge, Bob Le Flambeur, Le Doulos, Pickup on South Street, the Killing, and L.A. Confidential. None of those are technically con movies, but they all involve twisting, turning plots and mysteries or heists.
Layer Cake? Snatch? Lock, Stock and Two Smoking Barrels? As long as twisting plots are the order of the day. Not exactly the same subject matter as Spanish Prisoner, though Snatch is probably the closest of the three. Oh, and Usual Suspects. That too.
Suggesting Snatch to someone who liked The Usual Suspects is a bad joke. Yeah, they both have crime elements, but absolutely nothing else about the two films is even remotely similar. The atmosphere, the characters, the dialogue, the humor, the cinematography, the plots, the pacing, the structure--they're all 180 degrees different from one film to another. Really, I'm having trouble thinking of two crime films that are more dissimilar.
By the way, I love both films, but they're absolutely nothing alike.
Confidence with Ed Burns and Paul Giamatti is EXCELLENT! Great dialogue, great music, great performances, it's stylish and it's twisty. A plot hole here or there, but who's counting, right?
The Hoax The Distinguished Gentleman Boiler Room Confidence Derailed Heartbreakers Heist Leap Of Faith Lonely Hearts Mo Money Nine Queens Shade Six Degrees Of Separation