Does anyone know if it's possible to take in a regular bass in order to have it made into a fretless bass?
Depends on how you do it.

It is possible to do it at home, but its risky and can end up sloppy.

Shops will do it from anywhere from $40-100.
Member of UG's Keyboardists club. PM 4string-tsurigi to join.

Jimbo Wallace of the Godlike, Archaic, But Sexy Instrument Players. PM me to join.