What's a good substitute for sport peppers? Sport peppers are a key ingredient in the Chicago-style hot dog.
From Tomato Growers Supply Company's page about Sport peppers:


Sport: This Capsicum annum type of pepper is popular for its use as a pickled pepper to go on hot dogs and other sandwiches. It is especially well known as an essential condiment in a Chicago-style hot dog. Peppers resemble Tabasco peppers, but the Sport pepper is larger, about 1-1/2 inches long and 1/2 inch wide. They are medium-hot and produced in great abundance on sturdy plants. 75 days.

These are not readily available outside the US (at least in my region). What is a good substitute, particularly for making the hot dog?
Not sure where you're located, but any pickled pepper will work. In Europe and the Middle East, peppers like this are popular:



I personally use pickled jalapeños if I don't have sport peppers, but the ones in the images (Turkish pickled peppers) would be the most similar if you can find them.