How to build a global multi asset/diversified income portfolio

I was asked the following question via Chatterbox and promised to produce an explanatory article:

How to build a global multi asset/diversified income portfolio” - I, for one, would be really interested to read your take on this subject. In particular, it would be very interesting if you combined momentum strategy together with a desire for the portfolio to produce an income.

If I was to build an income portfolio I would want the portfolio to produce an income that kept pace with inflation, or at least had a decent chance of doing so. While capital growth in addition to income would be wonderful it wouldn't be my key focus. You can of course target both but in my experience if you want an income you are better off focusing on building a portfolio that can generate a reliable income stream and treat capital growth as a bonus.