You can do the same with a standard CBC study. Take the inverse of the number of concepts in each choice task to find the fit of someone who answers randomly.
Keep in mind, though, that it is much easier to "game" a CBC study. In MaxDiff you would need to be consistent across multiple tasks to achieve a decent fit statistic. In CBC I could still go through your survey very quickly and use a simply rule, such as always picking Brand A, or always picking the cheapest option on each task, to achieve a high fit statistic.