I'm sorry that I haven't noticed the new replies to this thread.
Regarding my library, I never got around to finishing it. However, I now need it for another project where a custom interface would take too long to code.
Due to this, I expect to continue my work on it and release it under LGPL at the end of august. I will post a link to the project once it's either done or at least stable enough for testing. I don't expect to include support for ARM in the first release though I will most likely implement that later.
To clarify to others, this project is about providing the same classes as the RTTI unit in Delphi. I have implemented most of them already though some features require the latest development version of FPC (a lot of features still work with the latest stable version). The invoke functions currently works with x86 (all calling conventions) and x86_64 (Microsoft x64 and AMD64/System V).