even though you want the light fixtures to mimic the fluorescent bulbs, you don't have to make them LIKE the bulbs. you can just make one area light for each light fixture, and create two cylinders with self-illumination and glow to LOOK like the bulbs.

are mental ray area lights visible in renders? if so, make them hidden! they should still emit light and such...

that should save you half the lights. if you don't get the same effect, just up the intensity.