I don't know how particular you wife is for buttonholes, but my Ultra Stitch 8 by Kenmore did a great job with buttonholes. The box says it has a built in buttonholer, but it you have to select three stitches. First stitch is a tight zigzag right side, bar tack, zigzag left side, then bar tack. I used it for a quite a while and it worked good for me.
I can never get the attachment buttonholer to work. I think there is just too much going on and it always goes awry.
Good luck!