Yes we did this on our last trip over Pres. Day weekend. I took my friends son and this was his big surprise. He built a double lightsaber (they are allowed for the same price) , he was really pumped cuz after getting of star wars and he saw the ones they have for sale, thats all he would talk about so needless to say he was pretty pumped to build his own when i took him to dtd.
Its a littel intimidating and I have to admit I had to ask for help, of course now i see it was easy..lol. Basically you pick what side youre on and build from there, they have instructions and you can pick from a few different designs for some things. When you get to the end and pay they then put the battery in to activate the lightsaber and they also give you a pin, yu can pick jedi or sith. If you choose the double lightsaber only one sides lights up but they let you take bulbs on both sides home....I think we ran into trouble cuz the instructions aren't set up clearly for the double lightsaber.
I think is looks pretty sturdy and it was pretty big, ours was about 6 ft, but i assume that a normal LS would maybe be half of that. If your kid is realy into SW then yes i think they will get a kick out of doing this just be warned theres a lto of kids just playing with it and parts are everywhere!!!