So.....I reached out to Martin with a hypothetical fretless inquiry....and now I have a fretless 5 on order. I'm basically leaving it up to him so I don't know all of the details. Will be similar to @77stingray 's chambered 5 string fretless, but 33" scale, narrower string spacing and I believe a BigSplitMan around the P bass location. ...maybe a little closer to the bridge. Either LaBella black nylon strings (most likely) or LTF's. A fretless was the only thing missing for me to use. Unbelievably happy to be getting another masterpiece from Martin. No timeline...when it's finished it's finished. Will be a nice surprise when it comes around. 
