Power supply unit quetion: is it possible....

[ninjamonkey]

I was wondering, would it be possible to shrink a power supply unit? cause I made a portable gaming computer, but its not really portable due to its size.

I was thinking of ways to shrink it. I came up with either a) have the psu being external allowing me to make the case much smaller since the psu would be external or b)modify the case of the power supply so that it takes up less space inside the case. I've opened my power supply already to mount it inside the case I made from plexiglass. It seems that there's a bit of unnecessary space. Am I right or should not mess with it?