Some evidence confirming our suspicions that topicalised and dislocated constituents occupy different sentence positions comes from Greenberg (1984). He notes that in colloquial speech the interjection man can occur after dislocated constituents, but not after topicalised constituents: cf.

(21) (a) Bill, man, I really hate him (dislocated NP)

(21) (b) ^✽Bill, man, I really hate (topicalised NP)