Excalibur said on the HCS Discord last month that the project was cancelled. According to him, since someone already made a high quality Superstar Saga OST and ripped most of the instruments in HQ using the method he used, plus other issues, he lost interest in this project.
by StarWolf3000 at 2:04 AM EST on February 20, 2019
Ripping the tracks and instruments is different than just making a high-quality OST rip of the game.
Agreed, high quality soundtracks are nice but most people would like to have a soundfont instead and may want to utilize those instruments for other purposes but it's understandable that he cancelled since this is not an easy task for anyone though I hope whoever did rip the instruments is kind enough to see this thread and upload the SF2 here for people who might be interested in having one.
Infomaniac95 already uploaded the MIDIs and the soundfont in this thread.
BIG UPDATE by Excalibur624 at 9:52 PM EST on March 9, 2019
I have big news: With the help of Infomaniac95, I finished up a complete Mario & Luigi Superstar Saga soundfont (with fixed PSG and loops) https://hcs64.com/mboard/forum.php?showthread=58975