Ter, let me attempt an answer:
I own one of Frau Ndegeocello's basses already. A Les Paul DeLuxe
with not the standard active Bartolini TCT set-up, but passive TB Plus pups made - wait for it - single coil. 
Gibson made that to her own specifications and the DeLuxe sounds a bit like a Jazz Bass as a consequence, the bass she would move on to after no longer endorsing Gibson.
I prefer it much to the souped up active sound of the original Bartolinis. The case even has a certificate from her.
I own four or five Ndegeocello CDs. I like her songwriting, her voice, her unglamerous, not cappucino-black, but real-black look (though I am aware that her interest in the other sex is of fleeting nature) and very much appreciate her bass grooves. She reminds me a bit of Sting when his bass playing was still on top of the game and not a side product. Sting played just a few notes and never anything fast, but some of those rhythms were intricate and he had a hunch for placing notes in places where you would not expect them. Frau Ndegeocello is like that too. While I am myself a busy, more harmonic and melodic player, than a rhythmic one, I do appreciate rhythmic players.
I first took note of Frau Ndegeocello like you, via that Mellencamp vid, perhaps ten years ago. I only learned years later that this was actually a Van the Man tune and that Ms Ndegeocello had given the original bass run her own slant. Excellent, though not at all how she plays on her own stuff, where her grooves are less busy and more primal (but great still).
http://www.youtube.com/watch?v=K0ov9082a1c&feature=relatedShe also slaps the way even I like it (and that is saying something):
http://www.youtube.com/watch?v=UpdzEpGIqtY&feature=relatedAnd my possibly most favorite song of hers doesn't contain any bass playing at all and is more in the Tracy Chapman mode:
Does she make me want to play better? Not exactly - her style and music is so far removed from mine and I'm not a black lesbian with a leftist political message (nothing wrong with that, I hasten to add!
) exploring the dark and most primal side of funk and soul. But I'm fond of her, enjoy her music and of all the celebrity pre-owned basses I have, her Les(bo) Paul bass raises the most affection with me, possibly because she has worn that bass in quite a bit, just look at the rusty pup screws in the second pic above. That comes from vintage Me'Shell sweat. Eat your heart out!!!
Have I given you a satisfactory and comprehensive answer, Ter?
Uwe
