Just to give you an idea, I will use over 4000 power modules on a ship no larger than 49 blocks, and I will do that pretty much with my first real ship, generating over a million power per second. Such a ship has no problem cloaking even while carrying a decent salvage array (as long as you haven't put too much else on it)....a total of 300 power mods...
Be aware though, that IS a cube, and a lot of people don't like cubes. You can deviate from the cube format, but your mass will go up relative to your volume if you use hull cladding and your turn rate will suffer.