Numerous as a determinative

Rodney Huddleston sends an interesting example from yesterday's Australian:

Many countries treat illegal immigrants and asylum-seekers far more harshly than Australia, and numerous impose mandatory detention, a provision explicitly provided for in the refugee convention.

Dictionaries treat numerous as an adjective, and I think that's right. The Australian is using it as a determinative such as many, which doesn't strike me as grammatical, and I can't find any similar examples. I do, however, find these, in which numerous is being used in the partitive construction, which typically requires a determinative.

1. 2000 ACAD Monist: later additions to the first published versions of the preponderance of the earlier essays. Numerous of the former do advocate a discipline, the cultivation of a form of ability
2. 1996 NEWS CSMonitor: Japan, Scotland, Australia, and Kenya. # LOS ANGELES # As numerous of the more thoughtful teens interviewed observed, a lot of L.A. slang comes from

They don't really work for me either though.