Ó Cuileannáin is documented in the Middle Cantred of Ó Cobhthaigh's Territory in the Genealogy of the Corca Laidhe. Woulfe also calls Ó Cuileannáin a "diminutive of Cuileann", which starts to look a lot like Collins. We should not be surprised if the names Cullinane and Collins are found to be interchanged at some point.
The name is sometimes spelled Quillinane in Clare and Tipperary, according to MacLysaght.
It is also documented as a Co Galway erenagh family.
A Donegal sept may be spelled Cullen.
In west Cork, Cullinane often looks like Callinan in old records. The Callinans were a separate family.