Hi! I recently released the first version of my new GBA tool icuGBA, a realtime memory analyzer built upon VisualBoyAdvance-M. Here's a screenshot of it:
And a here's
a YouTube video which shows it in action.
It's pretty straightforward to use. Green/red shows that a byte has just read/written, blue shows that it belongs to an instruction and has just executed.
Binaries and source available on SourceForge under GPLv3: https://sourceforge.net/projects/icugba/