This half fretless thing has me intrigued... recently, I was eyeballing a used Ibanez 7 string hybrd bass on Reverb with has 3 strings fretless, and 4 strings fretted, but the fretless portion is on top, and I believe is tuned E A D, while the rest of the bass is E A D G... but either way, I kinda thought the idea was real neat, as one could get two very distinctive voices happening at once...
*Plus, there's no law saying it has to be tuned like that 😉
But these instruments which you have posted here are beyond belief - especially that first one - good thing I was sitting down !!
Big George W
East Derby CT
Mobius Megatar - tuned in Classic Stick Tuning [5ths/4ths]
M.Megatar Toneweaver - tuned in Major 3rds
Warr Phalanx 12 - tuned in 5ths [melody], 4ths [bass]
NS Stick Transparent Green w/Moses graphite neck, tuned in 8-string Guitar Intervals
digitech, T.C. Electronics, ART, Lexicon, GK, Markbass, EA, Bag End, Guild/Hartke, SWR, EV, Radial, Ampeg, Trace Elliot, Furman