Detail #198: Some Uses for a Case Restricted to Certain Possessums

Consider the following statement:

I have a book

 We could consider having a special case that appears in this, giving us instead a clause of the structure

I am book-POS

Translating this into English as 'I am book-having' could make sense, to some extent. In fact, English almost permits this with a few particular nouns:

she is armed
he is tender-hearted
they are all peg-legged
etc

In English, suffixing -having, or using the past participle(!) of a noun tends to either parse as indefinite or somewhat inalienable possession. In the language we're now creating, we ignore definiteness. We might even exclude -POS from being used with inalienable possession altogether.

However, having a case that is specifically restricted to forming ways of saying 'have' might seem a tad wasteful, so let's extend its use a bit. We might use it whenever possession is changed in some way or other.

I gave you-ACC?/DAT? house-POS

The possession of the house has changed, and thus we mark the house with -POS. If the possession per se doesn't change, we use the accusative instead:

I gave you-DAT key-POS

In this circumstance, the case on the object distinguishes "lend" from "give", or "borrow" from "take". This case could of course also be used with specific verbs like 'marry' (maybe the subjects both are marked by -POS?), and maybe that's the one exception where the -POS case can go on subjects? Maybe subjects can be in the -POS case under a number of circumstances?