Long time lurker, first time poster. Found a Delta BOSS OSS at Lowe's on clearance for $56, with instructions but missing the spindle and other parts. Came with a set of 4 sizes of sanding drums, and bought a spare on clearance for $25.
Called Delta and they shipped all missing parts except the dust bag, free of charge. I figure I can hook it up to the shop vac, and I'll never miss the dust bag.