Since no one else has answered...

I have to admit, I got a little lost in the description. What I think you're saying is that you have lots of dark cherry (which will darken over time) and white fixtures. The window over the tub is also trimmed in cherry and the worry is that the light beige tile you like will make too big a contrast. You suggest drywalling a good bit of the window.

I vote no on drywalling the window edges. We have those kind of windows and they are *much* less interesting than wood trim - think 70s mass-build. I think you will find that your light beige tile is perfect as a bridge between the white fixtures and the dark wood. We did a bathroom (white fixtures) with medium and light beige/taupe walls, beige tile floor, and accented with dark brown and burgundy towels and shower curtain. This is a surprisingly pleasing combination. I can't take credit for having thought the whole thing through ahead of time; it was actually serendipity that I ran into that shower curtain at Target, and then the whole thing fell into place. In your case, the cherry cabinets will give that red cast, the beige tile will be your light, and you can think about an appropriate brown something or other to bring it altogether.

Just a thought.