As you probably have gathered from my few posts, I am a big Entwistle fan and I've noticed on his Buzzard basses that they all have 26 fret positions. I remember a post somewhere about the possibility of a triple pickup thunderbird-styled bass having to lose frets to fit the 3rd p/up, and was womdering if the good folk could make a fingerboard w/ 26 frets on a Series bass.
Seeing as John and Susan were designing the Dragon Wing together, perhaps John would have asked Susan to slip on a pair of extra frets for him!