Sears contracted Ryobi to make some Kenmore vacs for them in the early 1990's. Ryobi made several uprights for Sears, and now it looks like they also relabelled a Singer System 90 canister vacuum for Sears as well. Don't remember seeing these Kenmore canisters in Canada though.
Though Sears has ordered Kenmore versions of vacs from many manufacturers (Sanyo, LG, Ryobi, Sweden's Electrolux, TTI), the primary source for their vacs has been Burtman/Whirlpool/Matsushita. Whirlpool bought the Birtman vacmaking operations at some point, and then in 1990, Japan's Matsushita signed a joint venture with Whirlpool to make Panasonic and Kenmore vacs for North America. I think eventually, Matsushita (pronounced "Motsushta") took over the Whirlpool vac plant in Kentucky completely.
As far as Kenmore power nozzles are concerned, it seems that Birtman/Whirlpool/Matsushita continued with an ongoing contract from Centec to design and produce these nozzles for them over the past few decades.