I'm totally for the 'model every detail' style of modeling because as a way of learning how to model it's hard to beat. As you move into working on specific projects with specific time and resolution limitations you can always pull back and/or substitute bump maps etc.

As for duplicating objects as instances I have yet to find a way in maya of making the geometry independant - this can be a very frustrating limitation and as long as you aren't bumping up against poly count/file size limitations I like to use independant geometry. Ideas?? Comments??

I like the design - since you are looking for a mix of mechanical and organic, once you have the basic form finished try grouping it and putting a non-linear bend, lattice or other deformer on it to get some cool odd shapes that totally move your modeling into a new dimension.