This is very much influenced by anime of which mecha is a considerably sized genre. 
Panache and style is a pretty big thing considering the toy and model kit selling aspects that make the money for them. 

So could we have distinctive custom machines so long as they aren't hax? 

Can we be the pirate gang known as The Steely Dans on the yellow air-subship named Excelsior, that peacefully floats in the watey core of the great void. With customized mechs that have clear thematics in terms of looks and abiltiies?