hehe. a GT could be a feeder if you owned a large RTC. I've seen similarly large fish end up missing due to large cats being a bit frisky.
In any case, Jack and I just had a similar conversation in a different thread.
IF you really wanted a GT in that tank, you'd really only want to stick with one. GTs are pissy bastards and like to box now and then.
If you wanted to do something similar to what you are thinking, and were willing to do the research and maintainence to pull it offf, you could try a GT, two or three Silver Dollers (I really like silver dollars) and some hardy plants that could possibly be tossed around. However, my GTs have never messed with plants, but the rest of my cichlids all tear them up.
But, in a tank that small, it would be tough to keep a GT with any other cichlids. You'd want a GT and some smallish (not to small to get eaten) dithers.
It's doable. Not to sound belittling, but you could probably use a bit more experiance before doing a SA/CA cichlid "community" tank. It's tricky.