On 15 August 1965, The Beatles performed before more than 55,600 fans at Shea Stadium, New York, USA. In what was by far the biggest event to date of its type, that evening a dramatic revelation of the commercial possibilities of popular music took place, and changed the nature of the music business for ever. Simultaneously, despite using more powerful amplification than had been used before, the virtually non-existent connection between the musicians and their audience revealed the enormous technical and architectural challenges of large-scale concerts. Though this concert took place in a permanent building structure, the equipment it was hoped would temporarily alter its use for performance purposes was portable. That it was clearly inadequate for this task reinforced the need for new mobile facilities that would do the job better [1, 2].