There are no other Thomas or T. Penneys or Pennys in the 1900 census for Nebraska - at least according to the genealogy.com records.In fact, they list no T. Penney/Penny at all in the 1900 census, so perhaps their database isn't equipped to handle initials.
I don't have access to the 1910 census, but I do own the 1880 census so I did a lookup there for all Thomas Penney/Pennys born in 1861.There are two:
A Thomas Penny, son of Elizabeth Penny (widow)living in Abbottsburg, Bladen County, NC with his mother and his wife M. Eliza Penny.All were born in North Carolina.
A Thos. Penny, farmer - living in the Elja and Eveline Beardsley household.No birthplace listed for him, but both his parents were born in Ireland.Also with him is a William Penny, age 11.
Because I think the LDS 1880 census assumes birthyears based on the given age, I also checked for 1860 and 1862.Nothing.The next closest were a Thomas born in 1859 in Tennessee and living in Arkansas, another born in 1859 in Canada and living in Massachusetts, and one born in 1863 in Massachusetts and living in Massachusetts.That's it.I'll look up the info on those three if you think it might help.