It's been done before, in new buildings that had to pass inspection.
I'm rebuilding a kitchen with two cleanouts on the water wall, each about 6" off the floor.
How high is your cleanout above the floor?
I'm putting drawers in the base cabinets. Removing the drawers is easy as pie.
I'm also removing the base floor made of MDF or particleboard or OSB. Under the lowest drawer will be empty space. Removing all drawers opens up the space more than if the base cabinet still had its floor. So a body can get in there more easily than ever. But even with a floor inside the base cabinet, it's no problem to get inside a 36" base.
hope this answers your question.