Thanks for the replies everyone!
Sonas I got my information from "Sources for the History of Landed Estates in Ireland" Terence Dooley 2000. There's a card index file in the reading room in the NLI arranged by county and estate name. This will have two references. "E.C.1234" refers you to green volumes in the reading room. "box no.1234" refers to the Land Commission reference. The green volumes contain information on the contents of the boxes. Let us know how you get on calling them!
I know there are no estates records existing for the one I'm interested in. I even contacted a descendent of that estate to see if there were any held privately.
I think the inspectors reports that deal with the tenants could be a great source. For those of us with farming forebears I feel like it would be akin to military records of ancestors in the military. I'm sure eventually they could introduce some form of service where you could pay to view the records, similar to the valuation books, this would help support the resources needed.
As for the sensitivity of material issue, considering what you can already access, I can't see it being an issue, just an excuse. The people who decided to send them down to storage in Portlaoise are probably descendents of the people who decided to burn the 1800's censuses
