Ok, so one parting comment for the evening:
I was confused on how the verbs interact with the mappings in Rails, and would like to correct myself, but re-iterate my real point:

You would do
POST /categories
to get to the create action in the categories controller.

This makes more sense than what I though originally, but still makes less sense to me than having to seperately defined controllers… one for interacting with single items such as

POST /category (this would create a single new resource)

And another for interacting with collections
POST /categories (this would be for the times when you want to create several new items at once)

There have been plenty of people who have posted to this forum with problems along this line: how to handle batches of items… to me, this seems to be the correct way to do so… separate out what you’re really dealing with: either a collection (/categories) or a single item (/category)