It is not on LMA, and I did not circulate the individual sources, but I think a 4 mic mix I circulated from Los Lobos 2/8/07 fits this category.
I was at the SBD, and ran 414s (mid-side)/SD MP2 + 451s (DIN)/MOTU Ultralite. The 414s source sounded better on its own than the 451s, but did not have the crispness/clarity in the high end. The 451s alone, however, lacked the punch, full low end, and warmth of the 414s. Together, the mix was a lot better than either individual pair.
Where I believe a lot of 4 mic AUD sources are lacking is a poor combination of sources/gear. If on the same stand, I believe the center pair should be coincident - either M/S or XY - and the flanking pair should have sufficiently different and complimentary sonic characteristics that it is worthwhile to put in the extra effort.
I have not liked the sound of many 4 mic near-coincident x2 sources (ORTF/DIN/NOS), which seemed 'muddy' or 'soupy' sounding to me and often seemed out of phase. The jury is still out for me on split omni + near coincident, though I like split omni + coincident.