I didn't really buy it then. The places I heard this strategy discussed were where the Labour Party were describing this process in order to say how racist etc it was. If Crosby was as good as he was supposed to be (and apparently he was) then the dog whistle would have been silent, instead of attracting vast amounts of attention.
There is, however, an expert exponent of the dog whistle in modern politics. Despite never openly espousing any particular cause that might differentiate him from Blair, Gordon Brown has subtly intimated all over the place. To business leaders and the City he tries to portray the 'New Labour' visage, all about economic stability and fiscal prudence. To the centre left of his party he gives off an odour of sanctity and progressiveness, while to the headbangers he just lets it half slip that he thinks that some of these reforms have gone a bit far really.
Without ever nailing himself down to any particular position, Brown has managed pretty well at making almost everybody think that his Prime Ministerhip will entail a move in their direction. As a politician that's smart - as a Prime Minister that's damn difficult to maintain.