Hi Kay,
I'm afraid I don't have any iformation about your Patrick Corris/Margaret Clucas dilemma.
But I am interested in finding out more about what you have discovered about this Corris line (I occasionally fancy the idea of doing a 1 name study but usually get distracted by my other family history explorations).
I also have a Patrick Corris (different one) and it isn't actually that common a name from what I can see - only 4 'true' IGI entries online and only 2 in the 1841 census (1 is mine, the other may be yours as he is living with a Margaret and is around the right age) and only 1 in the 1851 census (mine) and then none in the later censuses (at least none born on IOM that I can see).
Anyway, if you have further info or would like any iformation about my Corrises, feel free to email me: rcorris(at)bigpond.com. Also check out my website at: http://www.users.bigpond.com/rcorris/Genealogy/heredis/accueil.htm (though please note it is in serious need of an update).
Regards,
Ruth Corris
Canberra, Australia