I wonder if there are any kind C programming wizards who know Postgres and might consider doing the open source port? It's beyond my Python programming skills and I dare not write crappy C code for fear of creating something nasty and insecure.

I can repay either by reciprocating with Python/web development/Linux/AWS knowledge, or if I have nothing of value to offer then I can offer thanks and praise.

The existing MySQL implementation is 460 lines of code.

There's a MySQL implementation here: https://github.com/libgit2/libgit2-backends/blob/master/mysql/mysql.c

There's a sqlite implementation too: https://github.com/libgit2/libgit2-backends/blob/master/sqlite/sqlite.c

Some relevant links: http://blog.deveo.com/your-git-repository-in-a-database-pluggable-backends-in-libgit2/