Your wife would end up loving a boa.
They are worlds apart from BPs.
When you have them out, they want to climb up instead of down, trying to get to the floor.
They have no interest in 'balling up and hiding'...they want to be right up in your face and doing/watching whatever you're doing.
Many Boa varieties stay relatively small, especially if you get a male.
*But* even my 7'+ Bob is a joy to handle.
He wraps around my hips with his body and rests his head on my shoulders and just goes along for the ride.
His only 'issue' is shoplifting things with his tail while I'm not watching so I have to be wary of what I'm walking too close to....:)
Maybe you you could get her to hold a baby or juvenile Boa for a while so she can see how much fun they are.
They grow fairly slowly so by the time it was "big", she'd already love it dearly.
:)