Have you tried doing this? What success/failures you have encountered along the way? What roadblocks have you encountered?
I stopped because I wanted to focus on recurring services and filled my schedule with these.
Most challenges with productified services come from risk management. The more bespoke the work is, the more risk you have, and the more risk you have the more risk mitigation tactics you must apply.
I suggest that you read a lot on preventing scope screep and managing time estimates before diving in. Jonathan Stark is a good start on that, he has free and paid materials available.
If you're referring to custom development but with a fixed scope, good luck with that. That's the whole job of a PM - you may want to get some help with that if you don't have experience in doing it.