The Campaign Builder's Guild

This is fascinating, actually. I'm so stealing that idea of chemosynthetic mushrooms for my Duergar... *yoinks*.

I watched a bit of a documentary about fish farms, actually. The effects of the waste on the environment were pretty shocking. You have to keep the waste moving and attempt to diffuse it pretty rapidly or you get serious problems on your hands.

EE, I get this nagging feeling that you really don't like 4E. Nothing that wizards or any other classes can do all day is really going to impact farming or demographics, except that armies might be on the look out for a lone mage commander amongst the opposing army. Then again, I'd probably be more worried about an enemy warlord than an enemy mage, but that's just me.

Bill's right; classed characters are assumed to be one in a million in 4E's meta-setting. Ritual casters are one thing, but most of the magicians of the world haven't even mastered a simple magic missile or scorching burst. Someone could make a magic item to replicate a certain piece of technology, but that's one of the awesome things about fantasy settings (and one of the few things I actually like about the Eberron setting, incidentally).

That's something you have to deal with in 4th edition. It ONLY has rules for PCs fighting monsters, so everything that's not related to PCs fighting monsters has to be made up by the DM. However, I've found that this can be liberating at times.