I have built about 10 take downs over the years now and am currently making 2 youth take downs for thePBS. I enjoy the projects and have had great success, however do not be dissapointed if a bow does not turn out. Chalk it up to a learning experience and try again. Figure about 120 dollars per bow. The folks at Bingham are quite helpful with picking out materials. Keep in mind you will need tools(I love an excuse to buy more tools). You need to make a form and heat box for starters. A band saw is useful for cutting the riser. I made a spindle sander but a drill press would work. A belt sander is a must. You can get a combo. belt/ dick sander pretty cheap. My first bow was a flat longbow. This might be a good place to start. The form is easy to make and there are many lessons to learn. Look to the Bingham site for pics.
You should get plenty of advice here, if I can help.
Greg Szalewski