As somebody who just traded their fretless bass for a fretted of the same model I would say that you should consider this option (trading) or possibly "do a Jack" ( @Happy Jack) and get another neck.
Firstly, you won't have to pay what feels like a lot of money for what seems like not a lot of work (luthiers please don't jump down my throat) and secondly you get to let somebody else experience playing fretless bass. If you choose to keep the bass, buying a second neck means that you get to enjoy a favourite bass in another way.