Lian Li PC-Q15
If you require more space, then Lian Li PC-Q15 could be an option. It has a volume of 15 litres and fits a standard size optical drive. The four feet look like wheels but don't actually roll. The frontal connectors consists of two USB 3.0 ports. The lack of any audio connectors is a drawback in our opinion.
There's room for a 3.5-inch hard disk in a type of hot-swap space along with two 2.5-inch disks. There's a single 12 cm fan in the front. It does its work fairly well, we measured between 38 and 42 degrees depending on the fan speed. The 40 dB(A) noise level is reasonable, and stays the same at both fan speeds.
The PC-Q15 has a 300 watt SFF power supply mounted in the back. There's room for a single-slot graphics card of up to 25 cm. The PC-Q15 is a nice chassis, but the price of £144 is too much.