what i did with wii was get a cheap replacement case from fleabay and put the drive inside (can also use leds for power and acess in wii buttons)
theres a few cases on fleabay you could either put the drive and power supply in the full case or if your feel like modding, cut the case in half so it would mount beside the PS3 and look like a modular extension lol!!
look into a SATA through connector/extender to mount on the hdd cover then you can disconnect external drive easily and neatly..
just a couple of ideas for ya, i have modded pcs anything from lcd screens in the case, to windowed hdds/dvd drives etc
There are 10 types of people on here
those that understand binary, and those that dont