PSU outside of case

I am considering having my PSU outside of the case as when it's inside it runs too noisily (thermic control) and also increases the case temp. When its outside it stays cool and silent, as does the PC.

Does anybody know of any problems I may have (with earthing etc.)? I plan to make some extension cables for the power leads and place a silent fan in a custom made panel where the PSU fits.

S