First, it's important to remember that 1) catchlights in some form or another are desirable, and 2) attractive catchlights are a side effect of good lighting. Eliminating them by changing the direction of your light source means employing lighting that is not terribly flattering for most portrait work.
Secondly, the idea that catchlight must be single, round, and specifically placed on the eye is rather old school, and really can only apply to studio-lit portrait work. Try photographing a person outdoors in "good" light, i.e. open shade or other soft, sun-sourced, diffused light, and you'll see larger, more numerous, multi-shaped catchlights. Is that a bad thing? Of course not. Your catchlights will look like your light and your light source.
If you're finding that your catchlights are distracting, you may need to reevaluate your lighting choices.
If you absolutely must have single, round, specifically placed catchlights....well, you'd hate most of my work.
