I like using the gba2midi and ssequtil for my own use (and no I do not submit them to vgmusic.com because it isn't my work and that they don't allow it anyway). Actually I just like listening to midi on XG drive. It does take time to "fix" the output midi because they're not in the standard midi bank. You can hear how it turns out but it requires a XG drive on your computer because I loaded them using XG banks and such. :)
But still I would like to see some sort of DS sequenced player in the future.