Steamer, suppose you had a PNP array, are you sure you could even use that due to the power dissipation? A saturated darlington(when used as a switch) has about 1.2V VCEsat and if it carries your 500mA bulb current, that would mean each transistor in the array would dissipate 0.6W! so, if you had 10 devices in the array, and all ten bulbs were on, that would be 6W of power dissipation. At 6W of power dissipation, your array package options are limited to around none. You would need discrete components..
I'm not familiar with the array you meantioned earlier, can you get a package that can disspiate that much heat?