From the shouting match!!, I learned that that system now works as follows:
They take you passport number (or maybe Garda card number).
Enter it into the computer linked to the Garda National Immigration Bureau.
If the computer is happy that you are legally resident in Ireland, a visa is printed.
If the computer is not happy, no visa, end of story; That is the way the system now works, no matter who you are, what letters you have, not even a letter from the Pope him self, what was done in the past, not worth my job issuing visa, any complaints about you will come back to the embassy and I will be fired. etc etc.
So to answer your question, Yes you should be able to just post in Passport and depending on what the computer says get a visa by return of post. It would even reduce their staff's blood pressure.
Towger.
Edit:
You need to hand in the passport, as the visa is a (security) sticker covering a whole page.
We are not part Schengen visa agreement because the UK is not. If we were, we could not have 'Common Travel Area' between Ireland and Britton. ie we would need passports to go to the UK. The UK are not as they do not have ID cards (any more), are separated by the sea and ruled Queen etc!
Towger