With much additional experimentation with the Korg MR-1000 DSD and my Nakamichi small diaphragm condenser mics with omnidirectional capsules, I found a really good positioning today. Although placing mics 6' in front of a piano on a stage or in a large recording studio probably works famously, it didn't work well in my living room. To obtain melded, blended and beautiful sounding music, I eventually discovered that the mics needed to be farther back from the piano. Placing the mics at 5 to 6' out from the piano produced too much of a mechanical, metalic, harsh and stringy sound. At the other extreme, 11' out, the sound was "swimming" in an airy ambiance. Thus, I knew the answer lay somewhere in between--which turned out to be 8'.
So in my situation, this is what I found works best (as revised 3/9/08):
Distance from piano: 8'
Separation between mics: 18'
Stand height: 5'
Upwardly inclined panning angle: 10 degrees
Mic orientation: not exactly parallel, but slightly converging.
During previous tests I became quite concerned that the piano's bass sounded weak, yet I knew it was powerful. (What Baldwin grand doesn't have a powerful bass?

) At first I began to dread that it was the Korg MR-1000, and that I might have to return it to Sweetwater. However, I soon discovered that phase cancellation was causing the low bass frequencies to fall out of the so-called "mono sum". So I separated the mics to a full 8', and voila!--the bass became rich and profound. Problem solved!
What I got from these many trials is that for room recordings, you really need to invest a ton of time in experimenting with the mic placements, separations, orientations, panning, etc. There is no one standard configuration that applies to every room. Rooms have different dimensions, absorption and reflective characteristics, pianos, and pianists, all resulting in very different accoutical results.
Now that I have this mystery solved, I can return to practicing to make a recording using the Korg!