I think you are correct about commercially available systems. However, I worked at a marine pollution studies lab for some time. We had an industrial-sized triple RO/DI system that absolutely did remove all particulate matter. The only ion left in the water was hydronium (H30+) but that is because water has an autoionization factor that makes it impossible to get achieve complete DI. Autoionization is the reason water can act as both an acid and a base--it ionizes itself. Water is truly amazing stuff!