Thank you Sue. My Thomas remains elusive, as he has been for about the last ten years for me. I think you're right - he will be found in the Ramsey register. The problem is that the available LDS film (Ramsey Burials 1836-1849 (MS09946/1/2 ) only covers 1835-1849 for Ramsey - nothing before this.

I've also searched:

Lezayre Baptisms, marriages, burials 1696-1849 (L22542/1/1)

Ballaugh Baptisms, marriages, burials 1810-1849 (MS10457-4) (his first son was christened in Ballaugh, so there may be a family connection there)

Maughold, St. Paul's Burials 1849-1869 (L22544-3-1) (searched up to census date in 1851).

I've also cross checked the death of every Thomas Kaighin I have accumulated from 1827 through 1851 and verified that none of what I have fits this Thomas.