build an excellent piece of furniture out of wood

I have a lot of design ideas. Right now, I’d really like to build a high quality solid wood storage unit. It would actually be two modular units that can be repositioned for multiple uses. I would more than likely use it as an entertainment unit at first. I want a really modern streamlined look with a dark chocolate brown finish. I’ve done some research and I think I need to use Walnut. However, I’m having a difficult time finding the wood I need since I think I’m needing boards approximately 2 inches thick, and 15 inches wide. Any advice would be much appreciated.