Case question

Sorry to interrupt the OT stuff with some actual conlanging, but
I have a question. :)

As you may or may not recall, I'm working on my first a posteriori
conlang, which is supposed to be Indo-European but not part of any
surviving real language family.

I decided to play with the active/stative distinction which early PIE
apparently had, even though the language otherwise has an accusative
case system similar to that of Sanskrit.  The active/stative thing
shows up in the fact that the subject of an intransitive verb
takes a form which is distinct from *both* the nominative case
(used for transitive subjects) and the accusative case (used for
transitive objects).

My question is: what should I call this case?  It is also used
as the vocative, but calling it the "vocative" wouldn't convey
its complete function.  I was thinking of just calling it the
"stative", but was wondering if there was any other precedent
which would be worth following here.

Thanks!

-Mark

Reply