I found a distributor in Western Canada for Southco products. I purchased new steel barrel lock keys from them. They had them in stock, and they claim that they carry most Southco latches and locks for RVs.
They also have heavy duty drawer slides and other interesting products.
Steeves Agencies Inc.
'The Hardware & Adhesive Specialists'
581 Marjorie St.
Winnipeg, Manitoba, Canada
Website: Steeves Agencies
Jim & Kate
2016 Creekside 23RKS, 2014 Ram 1500 Eco Diesel
1995 Monaco Dynasty 36', 2005 Honda Pilot