Daggerboards are fairly easy to make. A good source for building information is here > http://www.boat-links.com/foils.html
< as well as elsewhere on the net such as > http://mothboat.tripod.com/CMBA/Building/foils.htm
Personally, I prefer inert materials instead of wood. Inert materials don't rot, can't swell with moisture content, etc. so generally are better choices. HDPE, foam/'glass sandwich and other materials are common choices. They tend to be more expensive initially, but you gain this back in repair and replacement savings.