i just found this one
it's for the mora #333 but that's a 13" blade with a similar profile to the 1311... maybe it'll fit :P
I would suggest that you find out what blade thickness that sheath is made for. Most Mora and Machete's are thinner than the usual Busse Kin.
I wonder if there's a cheap Condor sheath that'll work...
I've actually been considering making a plain jane less expensive alternative to the usual custom sheath, but I'm still thinking about it, and then it will still probably wouldn't be quite as cheap as the production stuff.