Absolutely, Jon. A burlesque wouldn't necessarily require that or mean that the model was popular. You could burlesque something very obscure and the burlesque would still work because much of it lies in the performance, although in many cases it is still taking the micky out of a model. In some cases the burlesque would have been taking a rise out of a genre rather than an individual work. For quite sophisticated artistes like Cowell traditional ballads were prime targets with their sentimentality, simple structure and cartoon-like narratives. Some were delivered in exaggerated dialect and charicature but others were delivered almost verbatim as the model albeit with an incongruous style. Hence the fast jolly tunes for the likes of Lord Lovell and Billy Taylor. Read Cowell's song book and you wonder where the enormous popularity came from but much of it was in the delivery.