If I understand correctly, by "verbs of quality", we mean be-verbs, which are intransitive.

But what happens, when we have an intransitive non-be-verb, as is the case with {ratlh} ? Does it behave with regards to aspect, as a be-verb ?

For simplicity reasons, lets leave aside the {rIntaH}.

Suppose I write: {pa' jIratlhpu'}.

Would you agree that it means: "I have remained there, but now my remaining there is over, i.e. now I'm somewhere else" ?

Transitivity is irrelevant here. What's important to this discussion is whether it's a verb of quality, and whether that changes whether an aspect suffix is allowed.

Yes, I agree with your interpretation of pa' jIratlhpu', with the usual caveat that there is no now built into the sentence; the remaining could have occurred and been completed in the past (I remained there) or future (I will have remained there). But I recognize you were probably just using now for simplicity. I might go back later, or I might have already returned and I'm there again now, but that particular act of remaining is finished.

Here's a possibly easier to grasp intransitive action verb: quSDaq jIQongpu' I slept on the chair; I will have slept on the chair. It means I completed an act of sleeping, probably followed by waking up. That act of sleeping is finished.

-- 
SuStel
http://trimboli.name