There are a surprising number of manufacturers making wood/cellulose SIPs. Some have already been mentioned, but Bensonwood https://bensonwood.com/building-systems/panelized-enclosures/ is a leader in the field. Barrette https://www.barrettestructural.com/en/prefabricated-walls/, Factor https://www.factorbuildingpanels.ca/, Tooke Tree https://www.tooketree.com/ and Simple Life http://www.simplelifehomes.ca/ are among those offering customizable, carbon-storing panels.