[Orgmode] property searches for #+CATEGORY

[Adam Spiers]

I have several personal .org files, and several work-related ones too.
In each personal file, I have a line:

  #+CATEGORY: personal
  
and in each work-related file, I have a line:

  #+CATEGORY: work

I would like to be able to bind agenda custom commands to do tag
searches which are narrowed to one of these categories, e.g. "show me
all personal priority #A tasks".  Such a search needs to span *all*
agenda files, therefore the standard per-buffer narrowing provided by
the '<' binding in the *Agenda Commands* buffer is insufficient.

Would it make sense to include CATEGORY as a special property?  After
all, pretty much all other per-task meta-data ("TODO", "PRIORITY"
etc.) are already available via the property interface, and this way,
I could easily achieve what I need with tag searches such as

  CATEGORY="personal"+PRIORITY="A"

Thanks!