You can get a Detroit Locker,Air locker,Ezy locker,Lockrite,Torsen and almost any locker/limo
for this diff, so i'd be suprised if you could'nt get a full or mini spool for this too. Try ringing a good diff shop or a 4wd workshop.If there is nothing available you could proly get one machined up, their a prety simple device.
good luck.