Your suggestions were interesting. The 3rd option of only [using a space, no quotation marks] in the control name property (since control labels don't show up in datasheet view) yielded a blank field name, which is probably what you had intended.
But what I'm looking for is to hide the entire row of field names (column names) in the datasheet, so that I don't have any field names (blank or otherwise) separating my nested subforms. Anyway... heh heh, the [blank space name] doesn't work for the entire row as duplicate names aren't allowed.