It really depends on the resort.
We've stayed at Deluxe with a really nice twin size daybed (Contemporary) that DD slept on. It actually folded out lengthwise, and was a made up twin bed. I think an average adult could possibly sleep on it fine.
Other deluxes we've stayed at haven't had such a daybed. AKL didn't at all, from what I remember.
I think the GF had one, but it isn't in every room.
If you really need the extra bed, I think many resorts have a rollaway bed for an extra charge. I am requesting one at POFQ next month, and was told by the front desk that they have them. My kids won't sleep together.