Thinking out loud:

For true commercial production of a full device, the hard part 
would be getting FDA "medical device" approval, or getting it 
past Underwriters Labs. 

Either of these would be terribly expensive and thus prohibitive.

The more practical option, I suspect, would be to sell a kit....
Sell the multiplexer circuit and the programming, and tell the 
customer where to buy the accelerometers!

Or use the wireless version of the accelerometers, which
are more expensive but might already be UL approved.

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