Here's an example from Aristotle, Nich. Ethics 1103b-1104a:
τὸ μὲν οὖν κατὰ τὸν ὀρθὸν λόγον πράττειν κοινὸν καὶ ὑποκείσθω—ῥηθήσεται δ’ ὕστερον περὶ αὐτοῦ, καὶ τί ἐστιν ὁ ὀρθὸς λόγος, καὶ πῶς ἔχει πρὸς τὰς ἄλλας ἀρετάς. ἐκεῖνο δὲ προδιομολογείσθω, ὅτι πᾶς ὁ περὶ τῶν πρακτῶν λόγος τύπῳ καὶ οὐκ ἀκριβῶς ὀφείλει λέγεσθαι, ὥσπερ καὶ κατ’ ἀρχὰς εἴπομεν ὅτι κατὰ τὴν ὕλην οἱ λόγοι ἀπαιτητέοι·
Here, there is also a contrast between what it to be discussed later and what must be assumed from the start. And about English, the Ross translation has "But this must be agreed upon beforehand, that the whole account of matters of conduct must be given in outline and not precisely..." using "this" for ἐκεῖνο. I think the details of demonstrative use vary between languages. In English "that" is probably more neutral, but I'm sure Irene would agree that in modern Greek αυτό is more neutral than εκείνο, even though it refers to what's nearer.
I also found from Xenophon, Hiero 1.19:
διὸ καὶ πάντες ἄνθρωποι ἡδέως προσδέχονται τὰς ἑορτὰς πλὴν οἱ τύραννοι· ἔκπλεῳ γὰρ αὐτοῖς ἀεὶ παρεσκευασμέναι οὐδεμίαν ἐν ταῖς ἑορταῖς ἔχουσιν αἱ τράπεζαι αὐτῶν ἐπίδοσιν· ὥστε ταύτῃ πρῶτον τῇ εὐφροσύνῃ τῆς ἐλπίδος μειονεκτοῦσι τῶν ἰδιωτῶν. ἔπειτα δ’, ἔφη, ἐκεῖνο εὖ οἶδ’ ὅτι καὶ σὺ ἔμπειρος εἶ ὅτι ὅσῳ ἂν πλείω τις παραθῆται τὰ περιττὰ τῶν ἱκανῶν, τοσούτῳ καὶ θᾶττον κόρος ἐμπίπτει τῆς ἐδωδῆς· ὥστε καὶ τῷ χρόνῳ τῆς ἡδονῆς μειονεκτεῖ ὁ παρατιθέμενος πολλὰ τῶν μετρίως διαιτωμένων.
This doesn't quite seem like contrast, but ἐκεῖνο still refers to another point in addition -- I guess again ἐκεῖνο is used to explicitly point at something that follows, instead of what precedes.