I just wanted to say this to the DP community, When you are looking for someone to do work for you in the Buy - Sell - Trade and you ask for a professional to do the work and you also ask for a portfolio, you are never going to find what you are looking for. Every good programmer, linux admin, wordpress guru, or seo guru will always be under some sort of non disclosure agreement. So please, stop asking as you will never get a professional doing this.
Im really just expressing an opinion. If its a single person do the work, then I could see possibly asking for some references because you just dont know with some people on the internet. But if they clearly are working through a business, then I would think twice before really asking. I believe in the 5 years of server administration and programming I have been doing through my business, I may have had 2 customers who agreed to let me use the work I did in a portfolio.