I heard that I'll be teaching a Speech class for the first time this semester, so I went onto the Kotesol Facebook Group (very helpful: join!) and asked for some advice. People mentioned lots of stuff ranging from no book, to books, to video-taping presentations. One book that was mentioned a few times was "Speaking of Speech" by David Harrington & Charles LeBeau, so I decided to order it and check it out. It's quite expensive on Amazon, but I found it on Gmarket for around 15 000. And, it arrived 3 days later.
It looks pretty fabulous: it's beginner level, easy to understand, covers all the highlights such as posture, gestures, slides, etc and has fun, in-class practice things. Plus, there are around 8 (didn't count yet!) ready-made speech assignments, complete with evaluation grids. What more could a teacher want? Planning/executing this course will be not as overwhelming as I first thought it would be.