A hotdog is a frankfurter, it is a sausage, nothing more, just the meat grind is much finer. The imports, the world brands I like to call them, have a lot of additives and fillers. Real hotdogs can be found in Thailand, from Thai producers and local butcher shops. Finding these, however, can be a challenge. I found that Makro does carry Thai made hotdogs, next time I go and pick some up, I will take photos.
Update 4 Jan 2017, Tesco has a brand of Frankfurters called Mr. Sausage, they are good. These will be regular items for me now.
Update 1 Sep 2017, Tesco also carries a hotdog brand called Betagrow, they are also good.