TPLink WR703N

What?
The TL-WR703N is marketed as a "3G travel router". Its an easily linuxed router that costs £18, has a usb host port, ethernet and can be an 802.11n wireless access point or client.

Features

 * Atheros AR7240 CPU (400Mhz)
 * Atheros AR9331 Chipset (integrated wireless)
 * 802.11 b/g/n 150Mbps (130Mbps real)
 * wireless power output 20dBm - 100mW
 * 4 MB flash memory
 * 32 MB RAM
 * USB 2.0 port
 * Powered via micro-USB socket
 * Tiny form factor: 5.7cm x 5.7cm

GPIO
There are a few pads on the motherboard that can be used as GPIO

Power
There are also 5v (from the usb power socket), 3.3v (from the vreg) and ground connections available