I absolutely adore Spector, really I do, but I hardly consider them to have easy 24-fret access. I can get to 21/22 comfortably, but after that it's the awkward stretch everybody hates. When I think of easy access I think of basses like Ken Smith where playing in last position is just as easy as playing in the middle of the neck.
That said, for under $500, I haven't a clue about any recommendations.
Nathan Navarro Spector