The reason no work is coming in, is because you do not draw well enough. It is a great style to copy from interesting photographs. But there are a million, literally million artists on deviantart.com who can draw perfect portraits and make them look real and not painted flat from photographs with no 3d type shading. If I were you I would take an online digital illustrators portrait course. If you practice that, you will do great. But ya, you need training. At your skill level, with no training in person or online from a professional illustrator, no one will buy from you, unless they think it is a cute picture of their kid or dog.
I don't know what site to go to to learn. you can google "where is the best place online to learn to do portraits", to speed things up, if i were you, I would look up "chiaroscuro portraits" and see how they are lit. then, get good photos of your models with no distortion and use a light to light them up chiaroscuro style.., print them out black and white and trace them. then draw it upside down to correct errors. then right side up. sounds strange, but it is faster than getting taught.
for info on how to paint like an old master, or buy master materials and tutorials. check me out. good luck. http://www.dvart.net