Today Raspberry Pi announced a new model: Pi 3 Model B. It's a 1.2 GHz, 64-bit quad-core that yields a 50% performance increase over Pi 2. They've stuck with their $35 price point even though the new version has built-in WiFi and Bluetooth 4.1.
Another great device for Internet of Things applications that need the added power!
They're available from the usual sources (element14, RS, etc.)