Donovan,
Based on some of the comments above, and on my experiences, I suggest that your knife should:
Have a thin blade - since it will be primarily used for cutting vegetables. You can get a great slicing ability if you are willing to forgo the ability to cut bones. One of the most frequently used knives in our kitchen I made from a very thin Czechoslovakian blade. It has a deformation of the blade edge I haven't been able to work out, where my wife used it to bone out a chicken. Nevertheless it slices really well.
Have a long edge with a slight curve to it, to facilitate rocking cuts.
Have a length appropriate to the vegetables you cut most. Cabbages and melons dictate a longer blade.
In addition consider:
If you want the ability to ferry chopped vegetables with your knife you should adjust the blade width appropriately.
Decide if you want a point on your knife. If not, you will need to supplement it with another knife also.
You may also want to add an adornment or feature that is meaningful to you and your wife. My wife and I made a cutting/bread board of oak many years ago. The handle is two swan necks. She carved one, and I carved the other. That cutting board has been in use for many years and means a lot to us.
Please let us see how this special knife for you and your wife turns out.