Hi Jim!
I too am researching Butlers of Kilkenny - alas a rather gargantuan task! My great-grandfather Michael Butler married Mary Costelloe in 1873. Tracing his forebears has been very difficult, but I think there may be a connection with the Tullabrin (now Tullowbrin) area. According to his death certificate (1899) he was born 1849-50. The Costelloes were farmers in Tullobrin and through rental agreements etc I have established a sort of business link between Andrew Costelloe and Mary Quirke. Michael Butler married a Mary Quirke, both of Mount Nugent, (not necessarily the same person) in 1835 and they had at least 4 children (James 1837, John 1843, Michael 1845 and Michael 1849.
Do you have any indication that this family was connected with the one at Cloghpook?
Btw I found this in the petty sessions for 1851, through Find My Past:
Petty Sessions order books CSPS 1/5107
5th Dec 1851
Edwin Richards, Esq of Co Carlow against Michael Butler of Clohofook [Cloghpook?]
Trespass 23 and30 Oct