A little update: We've made a reservation at Sybaris, which is a chain of pool suite hotels in the Chicagoland area. Their website says couples only, but I wrote to them about it, and they were great about it, and gave me a special manager to call for a reservation for three. She was SUPER nice, and even apologized for only being able to take down birthday info for two people. She also went so far as to say that if we didn't all want to come into the office to sign the liability wavers that one of us could bring them back to the car for the others, and that the staff would be notified ahead of time. Very discreet and understanding.
I will let you know how we like our stay.