Well, I said that I'm going to post a beta this night.
I feel that I should have polished it a bit first, but whatever! Here it is. I'm really tired now and only managed to make one example MFA, which is just a showcase of the speed increase when using a callback fill data instead of fast loops.. check it out.
I also added an "Export to OpenGL" action in I/O. It lets you export to the currently bound texture. The OpenGL32 library is dynamically loaded when you use the action for the first time, so don't worry about any huge file size increase
It works very nicely, and supports transparent color & alpha channels.
My results on the example MFA are 0.35 vs 0.17 seconds.
NOTE: as I stated in the progress thread, it is not compatible with older versions. I've reached the action count limit (100), and had to modify the code for the ID masking (For some reason, ID's were multiplied by 10. I removed that.)... I hope this doesn't affect too much, I know that Werbad had this puzzle application for example