Not to cloud the issue, but is Jim Croce's use of the C# bass on a d-7 chord really a maj 7th or is it just another example of descending bass. The tune "Mr. Bojangles" uses the same descending bass, and to my ear it hardly sounds like a major seventh. I like to hear a richer tonal harmony, perhaps a flat ninth or diminished dominant chord before I identify a chord as acting as a major seventh. But then again, it's probably in the ear of the beholder.