The latest published mini-qmail kit is mini-qmail-kit-0.52.tar.gz .
This kit contains several files that help you set up a mini-qmail installation described in http://cr.yp.to/qmail/mini.html.
This kit just provides some installation/configuration utilities and additional makefile entries for compiling and installing selected programs for mini-qmail installations.
There are essentially no code changes from the original qmail source. The only exception is auto_uids.c. The makefile entiry is modified so that all the auto_[gu]id? variables have the value of 0, while these parameter values are generated based on conf-users and conf-groups in the normal qmail installation. A mini-qmail installation doesn't require qmail users and groups.
See http://cr.yp.to/qmail.html for general information about qmail.