You could look for something smaller on her registry and perhaps put it with something more personal.

I did this for a friend a few years back and it was greatly appreciated. I bought two casual wine glasses off her registry and put them with a nice bottle of wine into a big picnic type basket. I also threw in an inexpensive cute tablecloth and matching napkins. She loved it and it was different than a typical wedding/shower gift but yet still useful since it was from her registry.

Maybe get a couple of towels (if she registered for them) and put them with some fancy soaps, a candle and a 'do not disturb' sign for the doorknob.