Moving from Management Consultancy to Investment banking -getting modelling experience

I am doing an internship at a boutique Management Consultancy firm and I am in a client advisory/ strategy and research role.

I am experiencing what I have heard is a common problem for people looking to make the move from consultancy to Investment banking namely a lack of modelling experience.

What is a good way to get the right modelling experience without having done a investment banking internship?

I have an idea but not sure how much of an impact it will have. One of my family friends has his own non finance related company and I was going to ask him if I could produce valuation/produce models etc...of a company he is thinking of acquiring. Whether he is actually thinking of acquiring a company or not doesn't matter (I wont give the name of the company I value) but what is important is I can write on my CV I have experience of giving advice and producing models for actual companies etc... Is this a good idea?