It is here. STM32F746 has own discovery board.

Basic parameters of STM32F746:
- core ARM? 32-bit Cortex?-M7 CPU with FPU
- 1MB FLASH and 340KB RAM
- frequency up to 216 MHz
power 462 DMIPS/2.14 DMIPS/MHz (Dhrystone 2.1)
STM32F746

- USB functions: virtual COM port, mass storage, debug port
- 4.3-inch 480x272 color with capacitive touch screen
- Two ST MEMS microphones
- Two pushbuttons (user and reset)
- 128-Mbit Quad-SPI Flash memory
- 128-Mbit SDRAM (64 Mbits accessible)
- Two USB OTG
- ethernet connector
- Power supply output for external applications: 3.3 V or 5 V
- Arduino Uno V3 connectors

http://www.st.com/web/catalog/tools/FM116/SC959/SS1532/LN1848/PF261641?s_searchtype=partnumber