Re: Fretless guitar?
I tried a fretless guitar once, the big things I noticed are 1)lack of sustain...this is not as big a deal on bass as the strings are so much fatter and have a lot more inertia and 2)it's very hard to play chords that have more than one string played at the same fret such as the D-shape or E-shape. If you think about it, when you play an E for example, your middle and ring fingers are not at exactly the same place on the B and E notes (2nd fret on the 5th and 4th strings) but the fret stops the strings, so the intonation is on. It's really difficult to place two adjacent fingers at the exact same spot (where the fret would be) to get the intonation correct. For this reason, I think a fretless guitar might better lend itself to leads than rhythm.
If I was gonna get one, I might look into putting a sustainer in it.