Raj, a local business consultant, kindly took the time and interest to explore with us the business case for the millet thresher. Here are his notes.
Business case is from the business' point of view.

Value added is looking at the business from the customer's point of view.

Segmenting the market into two groups.

Market Segment 1 (MS1) are the family threshers, who do low throughput continuous threshing, generally without monetary compensation.

Market Segment 2 (MS2) are the commercial threshers -- women who thresh for pay ($1.5/day).

Net Value added by the thresher:

From: Raj <rajivs@gmail.com>
Date: August 1, 2008 6:48:12 PM PDT
To: michelle.marincel@gmail.com, dcohn@hampshire.edu, seb.rdz@gmail.com, thalia.konaris@gmail.com, brian@rasnowpeak.com, geo_yaw@yahoo.com
Cc: abs@mit.edu, blinder@olin.edu
Subject: Millet Ideas
Dear Team,
It was nice working with you on the high level business plan / value proposition earlier today. As a reminder, I am listing some of the things that we did not have time to cover in today's discussion:
1) The business case / analysis for Lease vs. Buy business models
2) Additional market segments (besides MS1 & MS2)- a fresh analysis will be required for every market segment, which will become clearer as you fix the geography that you plan to start in and expand
3) The values of X (price per kg for millet obtained by traditional threshing / cleaning process) and Y (price per kg for millet ed obtained by your process- due to better quality)- these values would need to be plugged into the model that we created
4) Intellectual property: filing a provisional (US & International) patent for your working prototype as you plan to execute this into an actual product
5) Break-even analysis, pricing / micro-finance to fund the sale initially to those who truly need it but cannot afford the upfront cost, licensing the design to entrepreneurs in other African countries so the largest number of people can benefit from it quickly etc. etc.
Hope this helps,
Best,
Raj