You need to find a semi-transparent tube about a meter in length and 4 centimeters in diameter. I can't think of anything specific offhand. Check hobby & craft shops, hardware stores, etc. Basically you want something like a white fluorescent tube without the endcaps, and not nearly as fragile. Then seal one end (even a circle of paper pasted on the end would work here) and attach a flashlight to the other end.
I think this would make an effective prop, even if it doesn't have the same cool factor as the ones in the movies. I don't imagine you're working with a George Lucas budget.