LEGO bricks and PC hardware are a better match than you might think - the case modding project of ATI-Maniac93 shows how to do it.
2000 bricks and power: Building a LEGO PC (33)
A heap of LEGO bricks is enough for the modder to create a PC case. While the HDD cage hasn't been a real problem, the motherboard tray was a bit more difficult since the usual spacer system couldn't be realized with the LEGO bricks. ATI-Maniac93 didn't just focus on the visual appearance of his mod, but also experimented with pneumatic components which he used for the optical drives for example. The HDD cage can move, too. See for yourself.