SEATTLEA building housing 10 adjoining lofts near Pike Place was purchased to be converted from airy studio apartments into a mayonnaise factory, Best Foods, Inc. CEO Peter Slater reported Monday. 'I took one look at those great wood-plank floors and two-story ceilings, and I knew that all it would take was a little elbow grease to turn the building into an awesome industrial workspace,' Slater said. 'There's this one sunlit spot over by the windows that'll be perfect for a two-ton industrial mixer. All we have to do is get rid of the leather couch.' Current residents were told to vacate the building by Dec. 1, but were offered first crack at the 80 $9-an-hour jobs about to be created, pending their acceptance into the building's workers' union. 