I'm into 'party trick' solo bass a lot, by that I mean stuff recognizable to folks at a party to vibe/sing along to, versions of,
My Funny Valentine, with the root note movement and the melody in harmonic's (on a 5 only)
McCartney's Black Bird, fingerpicked in tenths and chords (mostly) on a 4.
Jeff Buckleys Hallelujah, (which became popular here in the U.K. after and X-Factor winner covered it, typical) I've played for years with the guitar intro/solo on a 4.
And lot's of other weird stuff, but I've found in my scene, people would rather hear that kind of thing. This is my idea of solo bass and needs technique to play it, double trade-off, happy people, good practice on different techniques to communicate a tune.
As far as bass solo's, a recent Hadrien Feraud (guy is pretty new to me) youtube clip suggested that I've been living under a stone for a few years, it blew me away, different level imo, like Willis, Tom Jenkinson, theres a lot of it about ; )
Anyways just my 2, if it sounds musical, then it is.
I've seen a guy do the party trick thing. A whole set actually. It sounded great. I love doing that and tend to transpose common guitar riffs and basslines to play whole songs on one instrument. It's great to learn new stuff.