Every "drill to fit rim" i have ever seen is cheap as hell. Which leads me to believe no legit wheel company would ever concider doing that. You can always ask a wheel shop. I don't think you will have so much of a problem with weakening the metal though, aluminum is good for that.
Where i see potentical problems....1-The wheels wouldn't be designed to have the stress on that location on the wheel. A universal 4 lug is, something that not might be an issue
2-The wheel wasn't designed to have another hole that close. I've seen more than accoulple wheels crack around the lug whole, your wheels won't be designed to compensate for another hole so close.
In the real world, i don't know, but if you have ever seen a wheel fall off a car, you probably wouldn't consider risking it. I cracked wheel should be no different, if it cracked really bad and broke. Probably wouldn't get that bad before you caught it but still.