I don't know how realistic this needs to be or your hardware limitations so I can't say if under 45 mins is reasonable. You could have illuminated shaders for the surfaces and have area lights behind them. Area lights should be set to not be visible and you may need to unlink the fixture models from it.

If there are any volumetric effects in the scene then you may need a texture in the intensity that simulate the individual bulbs(an orthographic front render of the light panel would make a decent starting point for assembling such a texture). At any rate, you can have a pass for light surfaces that you can later use to apply glows and flares and whatnot.

Having said all this, multiple spotlights might still be less expensive.