He didn't say where it got the kit, but I found this site. These guys model Trek and other props out of clay, make resin castings, and offer them for sale on their Web site. The buyer then has to sand and paint the model. There are instructions and recommendations about materials. This PADD was the only one I really liked. I saw some phaser model there, as well.
If you look here and click on "Gear" then "Scientific," I think that shows the PADDS. There are also some finished props, such as tricorders and whatnot, in various sections of the site.
Some companies offer finished replicas that are expensive, but these are pretty cheap.
Anyway, there used to be a product on the market called an "electronic book," or something like that.
If some company wanted to make these Starfleet PADDS, using out-of-date CPUs and memory chips that were never sold, they could be made cheaply and sold at reasonable prices. Data could be loaded with a Memory Stick or even a floppy. When I saw this type of PADD, I could imagine that the black part on the sides was a floppy disk. The point is to make them cheap and give Trekkers one more toy that looks like it came from a Federation starship but actually works. It would just need some way to pick up data from a computer and display it for the user to read, be it USB, floppy, or whatever. I'm thinking a real working PADD like the one in the picture could be sold for under $50. It doesn't need a Pentium processor just to display a novel or your e-mail.