Quick update before the Best Product deadline:

The CORE module is done (at least on paper), the PSU module is almost done (I got to find a nice position for the power connectors for the submodules), while the INPUT and OUTPUT modules are yet under schematic review. I am also thinking of making a single supply version of the analog interfaces modules, but not now.

About the business plan required for the deadline: I have no idea how to make one. I've seen online that to make a proper one I should basically be ready for production, which is totally not the case since I still have to order my first batch of prototypes. Nonetheless, I have a plan in my mind that it's quite easy to follow and I hope it will be counted as a "business plan" at least for the sake of the contest (I know I have to make a proper one since I got to make a crowdfunding):

My plan is to start making the CORE module through a crowdfunding campaign, to sell it as a higher quality alternative to the Teensy Audio Board; ideally I will offer several modules on the campaign, to give the users several donation incentives (e.g. : first incentive is for one CORE module, second incentive is for one CORE module + PSU + simple analog IO interface, third incentive is for one CORE module + PSU + simple analog IO + pro level analog IO, fourth incentive is for 2 CORE modules + PSU etc etc), but I must be realistic and accept the fact that I may not be able to develop all these modules in time for a campaign.

As soon as the campaign ends I will keep producing boards either in house (if the demand will not be huge) or through external sources. To produce the boards in house I will need to buy some tools (namely: pick n place, reflow oven). 

Also, when the campaign ends I will spend the next 6 months to provide support for the modules produced during the campaign, through the means of a forum of some sort.

After the first 6 months, I will reduce the support time (in hope that 6 months of user base support will cover 99% of the necessary support information for everyone) and resume development of new modules (IOAPEX, PRO PSU, single supply analog IO interface, etc.).

This will eventually reiterate.

In a nutshell my idea of business is as follow:

-Make some MATT modules prototypes

-Make a crowdfunding to kickstart production of said modules

-At end of campaign, provide 6 months of support to said modules (or less if most of the support information has already been covered) while continuing production (in house or external fabs)

-When support phase is over, I will start development of new MATT modules

-After 6 months of prototyping and preparation, make a new crowdfunding campaign to kickstart production of new MATT modules

- Reiterate

I am also considering hiring someone in the future, either to help me with in house production, or to help me with the crowdfunding campaign (probably both). I will also have to invest on marketing/advertisement to make a proper campaign.