To complete the wish of nonchai: It would be wonderful if there would finally be more double bass RealTrack jazz soloists. The few Neil Swainson variations "wear out" really quickly.

+1 for both of both plucked and bowed double bass RealTracks

Another endorsement.
+1

+1 for RTs and MIDI.

All of the above, and consider fretless bass. I played for many years with one of the preeminent players, Mark Egan. He could sound as a ‘regular’ rhythm bassist but could also play marvelous leads.

+1

This would be awesome!

+1 I could really use Bass Solos.

+1

I actually came here to propose somewhat the same but for electric bass (of which there currently are none!), when I spotted this thread and figured I might as well tag that onto here instead

You can break any bass out into a solo with RealTrack Bass Samples for Sforzando using F5 stop the RealTrack bass then on the sforzando midi track F5 to start playing.
Watch Video
https://www.dropbox.com/s/3tp03y524o7i1yv/RealTrackBass-Sample.mp4?dl=0

Well obviously, and PG has already issued quite decent bass VSTi, both acoustic and electric, to use for that sort of purpose if one is so inclined. But that also means one would, for better or worse, be making those solos yourselves, which not everyone might feel up to scratch to decently pull of. And then, with the "real deal" you would just get something far more advanced and nuanced (eg slides & glisses etc) than the average user could, or at least not without investing some serious time and effort into some pretty intense midi tweaking.

Or, in short: The real deal is very much preferable

Have a try of UJAM MELLOW double bass fully working for 30 days, if you can use it it's half price at the moment.

UJAM 50% OFF
https://www.ujam.com/black-friday

They are RealPlaying as well as a sample set.
The Guitars and Bass will follow the BB Chord Output midi.
The Drums are RealPlaying also and have a sample set as well.