Well you can build it as weak or as strong as you want. You can work and buy a set of kicks for $150, or actually create something yourself that will give you good experience for $50 or less. With 2-3 layers of fiberglass over a t-shirt or thin cloth, it should be fine. These guys did it and it's working fine for them. Just remember you have a limited time to work with fiberglass depending on how much hardener you add (and how hot it is outside hot=faster set time, cold=slower set time) so generally you have 6-8 minutes to brush the resin on, which is plenty of time for one coat. Just mix it up in something that you can throw away, because when it sets, there's not cleaning out the mixing bowl.
I'm not sure on the sound, but then again, you can build yours however you want, whereas if you buy then, you're stuck with what the manufacture designed. Look at the kicks in this thread, and pull your ideas from them.
