Posted on the Netduino Community today:
The two first projects [touch screen, motion/distance sensor] I did today in a few hours (HW and SW; the little there was), which indicates basic prototypes like these don’t take much time at all.
It’s very effective to make small classes that provide drivers for different shields, different protocols etc, so they are plug-n-play reusable in new projects. E.g. for the touch screen prototype, the only software I needed to write was the driver for the touch screen, as MIDI and LED drivers were already in place. And now I have a reusable touch screen class too.
Even if the goal is to make a commercial cost/space-optimized product it makes sense to start with a Netduino/Arduino prototype to evaluate best components and circuitry, algorithms, test compatibility with other systems, possibly get early user feedback etc, before the production design is made.