"...into a 7x7x7 box..." there you go, you need to build a box to fit systems inside. Add a cockpit and you got the smallest fighter possible what looks like a box. Do you want your fighters to look like a flying box? Well I don´t and that´s why my 300 mass competition fighter is 40 meters long to fit this box into a hull that doesn´t look like shit.You can make perfectly usable ships on a pretty small scale at the moment, you just need to deploy them in large numbers. I think most of the early drones in the drone thread fit into a 7x7x7 box, and they work pretty nicely.
Edit: I´m sorry if i hurt the feelings of some borg.... your ships look fine... really.