You can stick them in a straight line, or a 1 x a x a panel, meaning you\'d have a one block high surface. As long as you stick block by block, they will work as one unit.
It actually depends on the shape of your ship. If you have a long by narrow ship, then your best bet is to stick them along the ship. Or build a room inside the ship which contains the power blocks.
Now, if you want a clean ship, you can make 3 blocks wall all over the ship, and you can hide the power blocks between the hulls.