I realize this post is old, but I wanted to put what we did up since I didn't find many answers anywhere.
We didn't feel like building out a box above it with trim, etc, mainly because I didn't know if I could get paint to match exactly. My main goal was to get the middle of the bulb past the cabinet door.
1. Cut out drywall & inset cabinet the 3/4" depth taken up by that drywall
2. Bought a sea gull light that comes out 10" total (biggest extension I could find that wasn't at Rejuvination prices).
3. Bought 2 round wood things from Joann's (bigger one a clock face) & a metal extension to the electrical box.
4. Put it all together.
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