Not worth the trouble. If you're intent on a new bass anyway, get one that was born a fretless.
I disagree here - it is relatively inexpensive to get one changed from fretted to fretless and I would much rather find a bass I liked (feel and tone) and change it than search for a much rarer fretless.
To convert it to fretless all the luthier does is pull the frets, fill them in and level the fingerboard and cut the nut slots down a bit lower. The last one I got done was much less than $200.
Dan K.
* or worse. Cases in point: I bought the P in my avatar as a defret(meh tone), refretted it & got great tone. I defretted a Washburn AB-20; went from *meh* to *I really like it*.