Sorry that this reply is to an old thread (I've only just joined this group), but hope it helps.
I have a Vox White Shadow fretless in dark brown, just like the one in the picture posted here. This is the original finish and I've seen two or three the same over the years.
I bought it secondhand in the late 1980s. It wasn't very expensive and I thought that I'd swap it for something better if I got on with playing fretless. When I came to change it I couldn't find anything within my price range that was as nice to play. The trouble was that the sound wasn't very good - quite dull and woolly. So I had a set of EMG pickups fitted. They cost more than the bass!! But they were definitely worth it and transformed the Vox into a really lovely sounding bass.
I haven't played the Vox for well over 15 years, but have just got it out, cleaned, polished and restrung it. I've just changed a Trace Elliot combo (the original TE, not the modern rubbish) to a Hartke HA3500 and HX112 which I collected yesterday. I've just plugged the Vox into the new amp and the sound is very nice - am definititely going to start using it on stage again (after a lot of practice - I've only been playing a fretted bass for all those years).
Cheers, Peter