Sub'd out of curiosity.
Mentioning Mongrain and McKee makes me immediately Outre from Jeff Schmidt. Similar-ish sound to the two acoustic players, Schmidt plays a piccolo bass and does some cool stuff with looping and effects.
Satori is my favorite track off his CD. He also has some alter ego stuff as Ruiner Severhead, check out
Bound.
Michael Manring is another of my favorite players who, while he's been around for while, has always seemed to be an avant-garde bassist. His signature Zon has detuners on all the tuners and each string at the bridge... and he uses them. I want to say his old website listed something like 15 different tunings (give or take) for his song
Invalid Link Removed and he plays three basses on
My Three Moons.
Hadrien Feraud is a relatively newer player on the scene (I think). I have to admit though, I haven't listened to much of his work because what I have heard swings more towards experimental jazz and a little left field for my personal taste (I'm into funk, r&b, Motown, soul, etc.) and he also seems a bit more about flash/technique... but that might go with the style of music. Check out a live performance of
Rumeurs to see what I'm talking about... I can appreciate the technicality, but it just doesn't
groove for me.
Rather than Feraud, I much prefer what players like Sharay Reed are doing with Gospel music. (I've been subbing for a black gospel choir for a little while now). Check out this
gospel music jam, a version of Joy to the World!
That's something I can groove to much more than Feraud, but I do realize it's a subjective matter of personal taste.
I hope those sort of qualify for what you're looking for!
Subscribed out of curiosity to see what other people weigh in with!
5sg.