I didn't realize that you were attempting to monitor 8 circuits.
So in what areas are you able to compromise.. cost, power efficiency, size/weight, ease of construction, etc ?
What is the wattage of the 8 bulbs?
How soon must a blown bulb be reported?
For the purpose of detecting a blown bulb, is shutting off or turning on all bulbs acceptable?
How much flexibility/control do you have with regard to modifying the control software used in this application?
How many PIC output/input lines do you have available?
The type of transformer I was referring too, is a small Hammond transformer that is about 1.25 cubic inches and weighs about 0.2 lbs.
If an additional 1.5 lbs is too much, then it is back to the drawing board.
Direct coupling of 240 volts to an opto isolator requires about a 3 watt resistor.