So today I discovered how to convert MIDI files to .SSEQ using official SDK tools. This was a test for modulation, however it seems the music file is broken. I presume it may be from when the music file was exported, though.
Attached is the MIDI, the text version of it, and the resulting SSEQ from the video above. Just like GBA Music hacking, ladies and gentlemen.
I also ripped this from the executable to convert this wall of text into the SSEQ. IT'S ALL THE COMMANDS! :D
Edit: After about a day of work, I made my own totally custom .SDAT.