Yeah, that thought crossed my mind after I posted my comment. This may be what the authors are talking about. I envisioned the problem a little differently though - consequentialism does seem to only need an ordinal ranking, while deontological theories just need to put actions in categories "good" and "bad" depending on context - at least based on my understanding of the terms.
Actually, neither of the papers that Luke linked to seem to discuss whether consequentialist theories can be represented deontologically. They seem more interested in the reverse question.
Did you mean to say that consequentialism needs a cardinal ranking, rather than an ordinal one? A two-category ranking is certainly an ordinal one!
This was demonstrated, in a certain limited way, in Peterson (2009). See also Lowry & Peterson (2011).
The Peterson result provides an "asymmetry argument" in favor of consequentialism:
Another argument in favor of consequentialism has to do with the causes of different types of moral judgments: see Are Deontological Moral Judgments Rationalizations?
Update: see Carl's criticism.