I found the piston circuit page on the MC wiki and yes, to answer my question, it is possible, however with multiple pistons (and it'll be around the peremiter), it becomes really complicated. Heck, now that I've thought about it, I have no idea whether there will be enough room in the lighthouse itself and of course, if I have to make it bigger, the whole setup can get bigger the more stuff I add.
It could be simplified by using two different sets (okay, maybe not simplified) of pistons, one pushing up and the other pushing down. I'd have to make the light emitting section into bands or something, no idea.
Using redstone lamps seems like a much simpler solution, even if a more expensive one, than a complex thing with pistons.
Having the light emitting part be in several rings might actually be cool though.