1:48 B-1B with lights and sound

I did a simmilar thing a couple of times many moons ago. I lit the interior of a 1/72 AC-130 gunship with grain of wheat bulbs. I hid the battery box in one of the wheel wells and put a hinge on it so it could be opened to replace them.

I also lighted the cocpit and all formation light with LEDs and put a motor to spin the rotor blade on a 1/32 AH1G Cobra. I used regular flip switches for both models. For the cobra, I bought a blinker circuit at Radio Shack for the blinking anti-collision beackons. Came out pretty good.

Sounds like a good project. One of these day's I'll probably outfit one of my planes with lights and motors too...

I would be concerned using mercury, especially around kids. A safer method to do the same would be to use a ball bearing or steel ball (I remember getting some ~1/4" diameter ones from Lowes a few years back for a project) housed in a tube... Radio Shack has a series called "Engineer's Mini-Notebook" written by Forrest Mims, and one of them shows how to set it up, though if I remember correctly, the main part is now sort of obscure/obsolete. Once you see it, you should be able to figure out a workaround if you can't find all the parts.

Another big concern is how to replace the batteries (they're going to die eventually). If I ever motorize something, I'll probably end up hiding the batteries in a base, but if you're going to embed everything in the body, you'll want to give it some thought.

One last thought would be to reinforce all of the joints with epoxy and/or sheet styrene... I'm guessing that weight of batteries + electronics will test the limits of the normal methods of construction.

Good luck.