You've found IT!
Most of the examples there come from the forum of CafeTropico,where I got the flagmaking idea. (if you want to understand it, you should go there and check out the forum, which is a great place by the way)
For the moment I've'got nothing better to write here but if I get a little more time, maybe i'd put some news stand here. (I said maybe, ok?)
You've (finally) found the page that will tell you anything that has to be known about flagmaking for the future hit from POPTOP, Tropico. We don't know yet if you'll be able to import yout own flags into the game, but I don't think so. Those flags are to represent yourself with a very personal logo that expresses your opinions on building (or plundering, whichever you prefer) a small island state in the Carribbean. You can visit all the section in the order you want to, but i'd recomend starting to look at some examples first. (this section is th most likely to be working first)