Originally posted by sulhan
I think Minolta is quite aggressive in their cost reduction strategy. If you look at the "x-rayed" diagram of the camera (can be found in www.minoltausa.com), minolta seem to use quite a lot of flexible printed circuits (which are 2/3 lighter than conventional printed circuits) like those used on inkjet pens. Lots of plastic/nylon gears and electronic sensors.
Given the size of the PCB's in a camera your point has little relevance. All modern cameras use flexible printed circuit boards where possible and have for the past couple of decades.
Nylon and plastic gears are used by most manufacturers, even in professional grade bodies. The main difference is that bodies like the F5 use higher quality (Mil spec for example) components.
Originally posted by sulhan
Plastics seem to be less succceptible to corrosion and also less risk of "oops i scratched the paint-off the camera while changing the lens".
Indeed plastics do tend to be less succeptible to corrosion in the conventional sense, however polycarbonates have serious stability problems with prolonged UV exposure and tend to work harden and stress fracture.
Originally posted by sulhan
I personally think that the most important metal parts would be the axle which couples the camera to the lens (for AF) and the lens mount.
Professional bodies use a full metal chassis, thus tying the film plane to the lens mount and shutter. This is not cheap to do and there is considerable machining involved. Magnesium alloys are the preferred chassis materials in most professional camera bodies as it has excellent corrosion resistance, dimensional stability and machining qualities while being lighter than the older zinc alloys used in the early 80s.
In an earlier post you said

"...come on....why do you want a heavy camera??"
Here's a few reasons why a heavier professional camera is superior to a light camera.
1)
Vibration Damping
Cameras have a considerable amount of internal vibration that needs to be damped out. Mirror, shutter and internal film advances all create vibrations that do effect the quality of an image.
The use of a heavy camera body lowers the levels of vibration considerably.
2)
Balance
A heavy fast lens (eg: 80-200/2.8, 300-400mm f2.8 etc) requires a fairly heavy camera body to be well balanced and to 'point' well. Pointing is how the camera and lens behaves when moved.
3)
Durability
Light weight designs are fine for casual and non professional use, however the use of heavier constructed components such as thicker gears and larger bearings and bushings on larger diameter spindles leads to a reduction in stresses on components and a longer more reliable life. The use of heavier duty motors and thicker walled plastic body components also add to the durability factors in a professional body.
Finally, if you are going to compare the Dynax 9 to any Nikon models it should be to the professional series bodies such as the F5 or F4, not to the semi professional or advanced amateur level bodies like the F100 of F90 series of bodies.