Does anybody know of any bars that are narrower than the stock ones? I'm not interested in going to clip ons, just hoping to find something with a similar rise and bend.

Why not just cut the stock bars?

A good vice, good hack saw, and a nice file to clean up the ends is all you need.

What about the holes in the existing bars to locate the throttle housing etc? Are they just round drilled holes or something more sophisticated?

There may be some punch marks under the switch gear as well. These are used as a guide to position the controls. I you buy after market aluminum bars like pro-taper or renthal they won't have any marks.

Use some tape on the bar to mark your cut line.