I obviously haven't tested every bass ever made but you can't get around the laws of physics. All basses have dead spots, with one possible exception, see below.
If you think the basses listed in your later post (4003, 4 Fenders, Ray, Gibson Tribute) have no dead spots I think you may be mistaking dead spots for something else. All of these basses have dead spots and no, I don't have to play them to know this. It's basic physics. Lots of people seem to think fret buzz = dead spots. Is this perhaps what you are referring to? Or maybe you've simply not noticed the dead spots yet. Lots of players don't notice dead spots until they suddenly have no sustain on certain notes when playing a gig through a large PA or when notes are "missing" in the mix when recording. Dead spots may be far less conspicuous in rehearsal situations or when playing through smaller amps.
FWIW I work at a guitar workshop and I've played hundreds of basses over the years. All of them have dead spots. Every single one. You simply cannot get around the laws of physics. Some basses have less problematic dead spots than others but they're still there.
I've been told that some headless basses with necks made from other materials than wood are supposed to have no dead spots but I have yet to verify this myself. It could perhaps be possible from a theoretical perspective but I won't believe it until I witness it myself.