My impression is that most Residence Inns (Marriott) have a few two-bedroom suites with two genuinely separate bedrooms and a sofabed in the living room. I'm not sure about the bathroom arrangement. I think the same is true for element (Starwood modern-design extended stay properties derived from Westin).

If the OP is looking for a two bedroom suite in a luxury hotel, going through an luxury travel agent such as Virtuoso could make sense. They might know the property; if not, they can contact the hotel for details, including the possibility of guaranteeing an additional room connecting to a one-bedroom suite. This is likely to be cheaper than a presidential suite, but of course won't be as luxurious or spacious.