lazjen, the software time on that is the only realistic cost, the hardware is not a large fraction of these mounts,
- GPS - only needs to be timing mode and within 300m position accuracy, so about $35 in single units for the module
- Wifi / bluetooth, cheap hardware, just lots of software time to make sure its rock solid.
- Ethernet, pre-built in many processors with an external Phy and port, cheap and stable network stacks exist.
- Encoders, The actual detectors are not the cost, its usually the printing that has the cost, take a look at the eq8's approach for reference, and how they where so cheap they didn't even clean the PCB's! and used the flimsiest possible connector, which was then hand soldered,
http://www.dangl.at/ausruest/eq8/eq8_e4.htm
About the CNC time, being able to reduce the number of operations and complexity of those operations cut down the costs considerably, you will have a mix of lathe parts for concentricity and mill for pockets and other non concentric features, being able to build within basic machine shop capacity would go a long way
Take standard stock sizes and try and build towards fitting as much as you can to fitting it into that so the external surfaces only need to be skimmed,
Again the more I look, the less I see the cost of the product in the hardware, and at this point I wonder about even the machining.