The idea sounds wonderful Mr Newton.
Of course, it`ll never happen, cos of Walkers absolute fear of live performance, which is a bloody shame.
The Scott Walker shows last year at the Barbican were stunning events, even without Scott himself on stage, but it would be a complete joy to watch/listen to him sing some of his more conventional songs. The voice arrangements and subject matters would lend themselves to an almost religous happening.
The nearest, and most successful exponent of such an event, for me, has been David Sylvian, who cuts from the same cloth artistically.
In this sense, i think, of the three, Bowie is the weaker artist.
My opinion only, of course

Love On.
Craig