Step 1: Materials
* EL tape
* EL inverter w/ battery pack
* clear nail polish
* Velcro strip
* hot glue
Since the t-shirt I modified was custom, I can't say where to get one. Here's one that is similar and even looks much nicer. In general, any t-shirt can probably be illuminated as long as the EL material can be put in place properly.
The GrayBean EL tape is high enough to cover the height of the lightsaber. Even though it is much too long for what is needed, the waste can be reused in another project. It has an inverter that plugs into the wall, but that won't get used. Instead, it is replaced by the GrayBean battery pack inverter which has compatible connector and 3 effects modes: constant on, quick strobe, slow strobe.
The velcro has to be no higher than the EL tape. I'm not sure if the self-adhesive backing version would work. I happened to have the sew-on version in my workshop.
Step 2: Cutting
Lay the EL tape on the blade graphic positioning the black power connector left of the slit opening. Cut the EL tape just a bit longer than the blade graphic. Shape the tip of the EL tape so that it looks like a lightsaber tip.
Cut a length of Velcro smaller than the length of the EL tape.
Step 3: Gluing
As shown in the image, I used too much glue on the loop Velcro strip. It squeezed out the sides. But because the height of the Velcro is smaller than the height of the EL tape, most of it is hidden in the end. I used standard size hot glue, because that is all I had. Maybe the mini hot glue would have been better.
After everything has dried and cooled, feed the EL tape from inside the shirt through the slit and attach it to the blade graphic.
Step 4: Sewing
And that's it. Pretty simple.