The 1850 Census enumerator for Surry County, North Carolina put Chang and Eng Bunker's family in the same household and then simply listed the children in order of age (partially shown in the image on this post). It even looks like the enumerator started to put an "&" after Chang's name as if he were going to put them on the same line. Our site contains the complete image of the Bunker's enumeration.
We've blogged about the 1860 enumeration which lists the twins households separately. Oh the things they don't mention on the list of enumerator instructions.
Those with an Ancestry.com subscription can search the 1850 Census--everyname index.