Im not sure how you would achieve this and maintain a good end result. Human fingers are fairly complex when interacting with objects as they tend to behave both in regards to the weight of the object, it's shape, as well as the position in which the object is held in comparison to the character. But even the mood of a character will be important, like if the character is angry they might have a different hand pose compared to a happy character. Obviously a lot more factors would have to be included as well.

My point is not that since a wrap script most likely wouldn't be able to do this, it would therefore be useless. But more that you most likely would end up having to modify your fingers regardless, because the script wouldn't be able to get it right anyway.

Looking at your image as an example and we imagine that the cylinder were held upwards instead, then the hand pose would no longer seem natural, as an example it would be unnatural to extend you index finger like in your image to counterweight the weight of cylinder should it be held upwards, unless you maybe held it above you head, but as you move it down below your head, your pose would change accordingly. So how a script would take that into account I have a hard time seeing. But its an interesting idea non the less.

Posing fingers can be time consuming, but if you make a small library with "default" hand positions it can speed things up. Personally since I work primarily with V4 and M4, i think I have around 10-12 standard positions for each of them and then I use the hand pose which comes the closest to what I need, most of the time you only have to make minor adjustment to the fingers to make them fit. I think the biggest problem when working with hands on 3D models is the lack of being able to curl the palm slightly. as you often end up with them being less flexible than a real hand.