Cliff,
The D3 is one hell of a tool, mate it with 28/50/85 Zeiss ZF lenses and you have a fairly compact robust incredible low light camera that will outperform your Leica (i had an M8 for 6 months) and offer you many other options as well. This week i have been testing the D3 against my Canon 1DS3 and it comes fairly close, in terms of colour and contrast i have to use my best glass, 35f1.4L /85f1.2L /135f2L to match the Zeiss glass, or for that matter the good Nikon glass. Had i not been a 1DS3 owner i would buy a D3 in a heartbeat, even though in real terms it falls slightly short of the Canon, just not far.