Domperidone + Ondansetron + Mosapride would theoretically be an alternative to Meto. Meto has three distinct features: D2 and 5-HT3 antagonism, and 5-HT4 agonism.
Domperidone: D2 antagonist but less
BBB passing ability than other D2 blockers, meaning less EPS and
tardive dyskinesia. D2 antagonist role to prevent NV is thought to be played at
CTZ located outside the BBB.
Ondansetron: 5-HT3 antagonist, which also prevent nausea and vomiting (NV) by blocking a 5-HT3 activity mainly at intestine.
Mosapride: 5-HT4 agonist, which accelerates gastric emptying, and to a lesser extent 5-HT3 antagonist. But they are available mainly in Asian countries.
I don't think there is any evidence about which antagonist (D2 or 5-HT3) has a central preventive effect on SN induced NV, so it's safe to say both antagonists are needed.
edit: D2 antagonist also acts at upper GI tract as accelerating gastric emptying.