subject api hooks

I would like to be able to put hooks on the subject API.

e.g. we could use logic to reorder the results. e.g. if I search for "smith", I would want people with the pennkey of smith to be returned first, then maybe people with smith somewhere in their pennkey, then people with smith somewhere in their name or somewhere else
e.g. we could have batched operations (query the subject source for 100 ids at once... maybe only useful for SQL subject sources)
e.g. we could have complex queries. If there is a search for "John Smith", my hook could take that and construct a more intelligent query that looks for "john" and "smith" in the search column, instead of the whole string "john smith".
e.g. we could have a hook which dynamically constructs the "description" field for different things in different circumstance. Not sure exactly how this would work, but in Thomas M Goerger's email on 7/24/8 he has long lists of subjects that he doesnt want resolved.

So how would this work?

• Use Grouper's hook mechanism if in grouper context, and Signet's hook mechanism if in Signet context? (I think this is the easiest)
• Or have a common hook mechanism (registered in sources.xml)? (I think this is probably the ideal solution, but would require extra or duplicated or more complicated generic code)