I thought the cushion was a piece of 1970's flotsam (mainly due to orange fabric covering!) but they are still out there. They are referred to as "kneading"-type lumbar shiatsu massage machines, and look to go for $60-100 retail although I could not find a ready source on ebay or amazon.
Alternatively, there is the low tech lumbar roller which looks like a "knobbly dumbell" type which looks to retail for $30+.
Does anyone use these type devices? I really hope they can bring some relief, as I now swear by mine.
Alternatively again, as Sean Connery whispered into the ear of the health spa nurse in Never Say Never Again, "You know, there is a more beneficial therapy for a man's lower back" ...