The thing is, mpbc contains only a tiny amount of custom code. All the code for converting models and writing block .gbx/.pak files is
already there in ManiaPlanet. mpbc just uses it in a new combination. Writing mpbc in its current state would be trivial for someone with ManiaPlanet source code/documentation; I have neither of those so I need to figure everything out by myself.
People shouldn't poke too much at Nadeo for being "slow" at keeping their "promises" though (did they ever *promise* custom blocks?). After all they are in the middle of developing two entire new games right now!