Cedar/redwood/pine/balsa would all be lighter. I teach high school wood shop and we have thousands of feet of yellow poplar here for about $1 a sq ft. Board is probably 25 lbs, heavy moving around the boat compared to other foam boards but not noticeable on the water. We have been making stand up paddleboards and surfboards for a few years now. Not very hard, you just need the right tools, I have a wood shop and finishing room at my disposal
My woody is about 1/2" thick actually and i just drilled holes through it and used ronix surf fins. Way easier than routing in fin boxes in a foam board. LOTS and LOTS and LOTS of research!!! I spent hours reading about surfboard shapes/rail profiles/tail shapes/fin size/fin shape/fin placement/fin angle before i decided on the shape of the woody and it rides exactly how i wanted it to. I also put a ton of bend in the nose to keep beginners from burying the nose. The foam top is gator grip for wakejunky. Give me a call and I can explain it better, it would take me hours to type everything here.
Here is the write up from the foam board.
http://www.wakeworld.com/forum/showthread.php?t=793716