Anybody have this problem with Warwicks?

Yep, thats right. But I can manage to reach the 24th with a bit different technique: put your thumb a bit lower on the neck and rotate your hand out and towards the body a bit. Works even on a Corvette 6

Oh and if you dont wanna do tha but still want to get those 22nd-24th fret notes, get a 5 strung high C or a 6...

 

I don't have a problem reaching the higher frets on the three high strings on my Thumb BO6. I do have pretty large hands. Remember, that 24th fret note is the harmonic at the 5th fret. Depends on the body and the player I guess. I wear my bass somewhat high, so perhaps that makes it a little easier, compared to some of the low riders out there.

 

That rotation is so natural I don't even notice it anymore. It's just a matter of getting used to doing it.

 

If you can't reach the 24, why not get a 26 fret thumb bass?