Ha! This is awesome! I did something similar in 2016, and called it something silly like SaaS-in-Box, but after integrating security, and Blueprints and multi-tenancy and caching, and ... (I do think I ran into some problem with blueprints, actually), ... I finally decided I was inventing Django-on-Flask and that it probably didn't solve as many problems as I originally thought it would.

BUT! That said - I think there is a solution gap here. Keep it up!