GHI Electronics  (known from the great Embedded Master™ module) have announced the USBizi module for the .NET Micro Framework . The module is really small and costs only $99 for a single unit. As it is the smallest .NET Micro Framework system it keeps all the unique features Embedded Master  has, like USB host and FAT file system.
Software: + Micro Framework 2.5 (3.0 soon) + USB Host (MS, HID, Printer and more) + FAT File System + Peripherals (SPI, PWM...etc.)
Hardware: + 72Mhz ARM7 Processor + USB Host/Device + Plenty of Digital I/O + Interrupt Inputs + SPI (8/16 bit) + I2C + 4 UART + 2 CAN Channels + 4 10-bit Analog Inputs + 10-bit Analog Output + 4-bit SD Memory Interface (uSD connector) + PWM + Low Power and Hibernate Modes + -40 to +85 Operational + Lead Free