How much capital do we need to generate an annual dividends of 20k?

500k @ 4% would do it. A balanced or sightly conservative dividend paying portfolio should do just fine.

Something like a 50% Fixed Income / 35% Equity / 10% Gold / 5% Cash portfolio is something I would look to create.

If you're looking at 5% of returns, you'll be looking at roughly 400k. :)