>I simply looked up the history of naming the D## cameras and >found that the lower model, D40 moved eventually to D60 and >then, in a way, made the jump over to the D3000.
My earlier reply touched on this. To be accurate, the D40 was announced in November 2006, and the D40x was added in March 2007. The D40x was pretty soon replaced by the D60, in January 2008, while the D40 continued. The D5000 was announced in April 2009, in effect sitting above the D60, then in July 2009 the D3000 was announced and once it was available the D40 and D60 were discontinued.