I got my fretless about May last year, and after playing it almost exclusively right up until about January this year with flats (TI's), I decided I wanted to see if I could get that beautiful roundwound singing tone. So after I put some D'addario EXLs on my fretted, I took the TI Jazz Rounds I'd had on it and slapped them on the fretless. Months of playing followed, and unfortunately at the moment due to a little too much slapping and not accounting for the fact that the strings are flattened, and hence sharpened by the fact they were soft nickel and on my fretted for over a year, the fretboard is getting kind of "fuzzy" if you will. As such, I've had it out of commission until I can get the board resurfaced and finished with some kind of urethane. Because of this, I've been on my fretted ever since about late April -- and trying like hell to make it sound fretless...with a surprising degree of success. There's no faking the real mwah or the powerful slides of a fretless, but with sufficient practice, you can get one of the best parts of a fretless -- that beautiful singing vibrato -- to come out of a fretted bass. Also, the neat harmonics tricks commonly associated with a fretless (sliding/vibrato natural harmonics specifically) can be pretty well adapted here as well. Of course, as soon as I've got my fretless done up with a newly surfaced and finished board (and new TI Jazz Rounds) I'll be back on it asap, but this has definitely been an interesting experience for me. Anyone else try something like this?