I fully concur. Given that a Wallace Tree Multiplier is what one would consider to be a niche design (although common), it is unlikely that someone has working code to hand.If you insist on ready to use code, then most probably no one in this forum would be willing to provide you with one (at least not me). However, if you are willing to code the function yourself, then I'm sure there are members of this forum that are able to help you.
For a start, if you are not familiar with Wallace Tree multiplier, have a look at Wikipedia article to get an idea on how it works. There are also other resources available on the net on that subject. Google is your best friend.
If you decide to have a go and encounter any problem, then you can post here and we will try to help you iron it out.