I think all this noodling over homeless solutions gets political real fast... like the moment any kind of organization or "meaningful" scale presents itself. It seems to me that this, at the very least, means coordinating with some kind of larger body - such as a larger organization already assisting with domicile-related matters, a disaster-related outfit or government at some level.
Personally, I'd like to see a well thought out path to a good homelessness solution and contribute where I can to something that will grow organically and rapidly while wasting as little material and human resources as possible. SIPs do seem like they'd fit into such a plan. I wonder what it would be like to consider making them if none were available/economic. I wonder about designing a flexible transformative capability into them - allowing them to be used initially, say, in temporary situations and later gracefully re-used for more permanent structures.
When I got orders for large numbers of hexayurts a few years ago, I set up a very simple manufacturing facility - hiring and training a few guys who were probably pretty much like many homeless types - addiction problems, some prior incarceration, few skills... However, with good simple set-ups and training their first-off yurt (with bevel cuts etc.) was +- 1/16" accuracy on the whole assembled, taped polyiso structure. Could solve a couple of problems at once...