Well, I'm working on suiting my son up and had some ideas about doing the jet pack. So, I started there. 1st) For a child, it has to be light-weight and comfortable. 2nd) Cheap - because he won't be able to wear it but for a few years.
I had a lot of strofoam siding material leftover from making my pack. Went to Wally world and bought some circle, and cone shaped floral foam. My wife was just about to toss out two perfect sized shampoo bottles for the tanks. Bought 2 of the medium sized "For Sale" signs at Lowes, and I used sintra for the backplate.
Here is what I have so far...
I don't like the rocket, so I'm going to keep looking for someting better.
I used some old spray paint plastic tops for the bottom of the tanks, and powerade cap for the top. I bought a pack of those furniture bumper thingees to make the piano keys. I figured I could use a large-penny nail for the stablizer, and I have a little screw-on valve-cover LED to use for the light on the opposite side.
Here is a comparison between his and mine for size.
I even have a cool set of labels for it - Thanks to VashDstampede. The chest emblem on the upper-left is a normal-sized one.
Oh, and here is a picture of the collar and backplate with it.
Comments welcome (and of course ideas for the rocket too!).