Here’s a neat little Kickstarter. It’s a motherboard-sized board onto which you mount your Raspberry Pi. It includes space for a 2.5 inch SATA hard drive (although not sure how this connects to the Pi), a 4-port USB hub, an RS232 serial port, broken out GPIO, a real-time clock, a built-in temperature sensor and a built-in IR remote module.
Pledges to receive the board start at £40, which isn’t bad.