I started looking at trees that would make good sustainable food/oil/biomass sources for a tropical environment and found three. The first was the Chinese Tallow Tree, discovered on the biopod website. Interesting, I thought, but invasive and hardly edible. It turns the soil somewhat inhospitable and is considered a weed in the southern states. The next I saw was Oil Palm, which seems to be a bit labour intensive for not all that much production... to be honest, the section on cultivation seemed a little over the top. With the Tallow Tree, you just kind of step out of the way and it takes over. With the Oil Palm, it seems you look at it funny and it dies.
Finally, I looked back at an old friend of mine from Sri Lanka, the Drumstick Tree. To be perfectly honest, I ate the green bean-like things in curries and I think I had the leaves, too... and I found neither of them terribly palatable. The thing is that it has a great nutritional and medicinal profile, and isn't toxic, and doesn't seem to be tough to cultivate. There are loads of sites dedicated to it (just check the links from the wiki page).
The Green Gap
In the Cold War, we feared a Missile Gap was a strategic weakness. Nowadays, we must awaken to the fact that the Green Gap is true strategic weakness: the nations whose economies will thrive in the coming years will not be those with the biggest factories, but those with the most sustainable, efficient, and ecological markets. What we require is a Strategic "Green Reserve" of ecological design to weather the coming changes that both climate and resource scarcity will force on the international economy.