BA, CSA and LH
Regional come to mind. It really is the same seats but with a different headrest and sometimes (BA) more pitch (BA has about half the seats at 32" and the rest for EuroTraveller at 30". The seats on the BA
ones go from the back row forward as they are near the entry door.
Here is one from CSA. Note the token "Business Class" logo on the curtain. Don't think much differs from Y class cabin wise but obviously the service would be different.
If you are asking could an ATR have like a 1-2 arrangement I think it usually means separate seat tracks as on the CRJ. Quite expensive and not necessarily possible.