well, I made a commanche that has 2 purple beam lasers
what I did is attach it to the rotor bone, it is so short that you wont notice it comming from there, you just see the al important beam
to make them different I made 2 weapons versions of the original beam, and besides changing the color I varied the range, so that they wont fire exactly at the same time, they work fantastic, but indeed you do nee a bone, But I guess any bone on the model will do, even a wheel bone.