So the collective forum answer is....
All of them! They all make the best fretless. I think what you are comfortable with for a fretted bass you might love without the metal bits. Or you could go for something completely different. I didn't hear anyone mention the Classics but if that is an option it may be awesome with the mutes and all.
i like my sr4 30th fretless.. mahogany goodness!
MrM