RoC campaigns does exits, but are very rare. Only difference is these are just seperate RoC maps (w3m) that should be put in same folder* and the maps shall NOT have their names changed.
An example of a RoC campaign I've played is a RoC version of Nature's Call - The Spider Queen.
If your campaign is just one file and in w3n-format, the you'll need TFT to play it.
The seperate map method is also effective for multiplayer campaigns, though I think it wouldn't work very well in Battle.net.
*the folder path should go like Warcraft III -> Maps -> Campaigns -> "Name of Campaign".