Neither have I, but discovered it by accident. This is what it says on its
To address the old-age and technology of RPG Maker 2003′s RPG Runtime engine, a replacement will be written that implements more modern features. This is intended to work both as a 1-1 replacement for the RPG_RT.exe executable and as an extender to allow features which would be cumbersome to implement conventionally as event scripts.
There are also a long string of bugs and feature requests that will be addressed with this engine, especially the more commonly known battle bugs and speed/agility problems.
Sounds like it would be useful, except I haven’t had a chance to use it yet. I’d have to dig my RM2K3 – it can be used with RM2K and RM2K3 – and its projects out of limbo, as it seems to be semi-reliant on the Maker’s base materials, the RPG_RT, to work. When I have more time I may check into it further.
(I wonder what the implied legalities are with this.)
EDIT: It appears that this project has been cancelled. You can most likely still download it if you search for it.