My guess is that the responses; if any will be as varied as they come.

The biggest challenge for your case will be getting some existing member from the target SACCO to front your application.
From my grape-vine & background checks done a while in the past; I'd recommend these two:

Safaricom Investment Co-operative : http://www.sic.co.ke/
Maisha Bora Sacco Society : http://maishaborasacco.com/index.php

Notes :
SIC ----> I'm not sure if that meets your Idea of a sacco. Joining Requirements are straightforward.
MashaBora ----> Good luck in getting someone to introduce you there.

PS : I'm not a member of any SACCO at the moment.