Yeah I'm avoiding PWM because of complexity and flicker. Having switchable rows might not be a bad idea.PWM might drive up the complexity and cost, especially if you're in a DIY mood. What about simply installing switches that turn off/on individual rows in your light?
That will work too... nice and cheap! But like Ben said: these things can rack up current quick!As for power, I have a ton of old 12 volt laptop supplies laying around that I can use for mains power and for battery power I was thinking of using some of those big LiPo packs they use for RC planes as they're inexpensive, have impressive power density, and can handle whatever current I need to pull out of them.