Influenced by William Friedkin's Sorcerer (1977)?
I just watched William Friedkin's Sorcerer (1977) http://www.imdb.com/title/tt0076740/?ref_=fn_al_tt_1
and couldnt help thinking of Fitzcarraldo...a number of similar themes and mammoth set pieces of production. Its very likely Herzog wouldve seen it, what with Friedkins reputation, the size of the budget, and the produciton stories that wouldve done the rounds amongst filmmakers.
Its just a theory, but even so I think the two films make an interesting double bill, and if you enjoyed Fitzcarraldo and are looking for something similiar give Sorcerer a try.