I don't know of anyone selling long hives in your area. You might look to someone who builds top-bar hives and ask if they'll make you a "Tanzanian" top bar hive with a rabbet (i.e a long hive!)
But of all the hives short of the barrel tbh, I think a long hive would be simplest to build yourself and maybe worth a try.
Make sure you figure out the dimensions in advance so that your chosen frame size will fit, with bee space on all sides. I also recommend making the length a convenient multiple of the width of migratory tops. This way if you are inclined to buy rather than build, you can purchase everything but the box itself. A rectangular box is within most people's ability to build even if you don't have much experience.