Nice Stuff Solo!
I think it is a great idea to create your own - I want to take the time to do the same some day. I like the organic shapes you have started with - very contemporary feel to them all.
My suggestion would be to look at some of the manufacturers sites you think are cool and closely observe some of the finer details of their pieces. It's often the little things that make a difference. Here are a couple of my favorites;
http://website.johansondesign.se
http://www.fritzhansen.com
http://www.artifort.com
http://www.moroso.it
http://www.bebitalia.it
http://zanotta.it
http://portal.cappellini.it
There are both practical and material influences that can affect your designs. For instance - the first 3 pieces rest flatly on the ground plane in a suction cup manner. This isn't usually preferred from a material standpoint as even the slightest of feet or pads that raise it off the ground provide a little airflow, and protection against a liquid spill on the floor surface. Also - some of the pieces seem just a little too upright to be comfortable, and even the slightest hint of a more body conforming seat / back can add a lot of realism.
I assume you are using the sub-d and smooth ruby to achieve these very flowing results - wonderful job!
Bytor