Hey MK71, great endeavor. Hard surface modelling is challenging, and at the same time gratifing when you do it right (at least for me that is). I love it how you got to have a strategie and plan some things ahead, not just do stuff as if there is no tomorrow...
Some of your shapes look OK as they are right now. But, do they stand the challenge of subdivision? Or do they turn ugly?
I leave you with this, it was so usefull to me and I think everybody should see it (it is done in Max, but applies to any 3d software using polygons really):http://area.autodesk.com/tutorials/inorganic_modeling_fundamentals_part_1http://area.autodesk.com/tutorials/inorganic_modeling_fundamentals_part_2http://area.autodesk.com/tutorials/inorganic_modeling_fundamentals_part_3