How many plug-in systems are you allowed?
I don't know much about them other than they're around 800w, but what's stopping you having more than one?
I ask not to actively circumvent the rules, as such, but I was thinking of having one for west and one for east - both vertically mounted. To me, that's fairly harmless compared to just buying lots and plugging in all over the place if you were trying to cheat the rules, whatever they may actually be.