Your context may aid in the selection of a single word that includes both ladies and gentlemen.
For example, if the ladies and gentlemen are guests at a social event of function, you might say:
Do you, distinguished guests, need anything?
Or if the ladies and gentlemen are members of a club, you might say:
Do you, kind members, need anything?
Or if the ladies and gentlemen compose a group of visitors, you might say:
Do you, welcome visitors, need anything?
These examples may sound artificial or overly formal, but they indicate that you may be able to find a good single word to fit your specific situation.
Addendum: I just remembered another gender-neutral word that works in many situations: folks
folks: people in general—used to talk to a group of people in a friendly and informal way
Do you folks need anything?