##Yes You can
This video explains the phenomenon, and how to build one:
Basically, it works as you have said, a long loop of hoppers will keep a chunk loaded, but the hopper chain must start in the spawn chunks. You can use chains of hoppers to basically extend the area of chunks at spawn that is kept loaded.
In this diagram, the yellow area represents the spawn chunks. As long as the hopper chain starts in the spawn chunks and leads out of it, those chunks will all be kept loaded.