Some nice ideas Luc, there certainly seems to be something about this size bracket that almost requires people to generate some inspiration in seeking the boat for their own purposes. For the same reasons the presently non existent C40 (as opposed to Exhilarator 40) is likewise not far from my thoughts.

I think you made a typo for WW hull
Overall height 1.95m, length 10m but really saloon/cabins is about 6.7m (between beams)
Just an observation but the LW hull (height 0.75m, length 15m, beam 0.45m) being even narrower than 20:1 seems to be very skinny, Im just wondering is there really any advantage to that?

Id like to know more about your saloon plan as that is where my attention seems presently fixed, my own interpretation follows.