this is all fine,
You say: "but they are not designed to be used as category page or links page."
I can see that,
but due to the WP structure all these links exist and could be used ...
- why not using it?
- and why should they be unusable?
- any other custom post has all functions inherited be post_type post or page ...
I would use it ...
As I do with custom taxonomies here: "custom post type plant typ = tree": http://pflanzen-bilder-kaufen.de/pflanzentyp/baum/
This is the original link structure for a link category:
http://ktse.de/?taxonomy=link_category&term=links (it works)
I hope I could be a little bit uh upgrading, up bringing, rethinking?
Anyway, I think it would be great.