I'm using an old slotted 4x5 holder and adapting an RH10 lever wind roll holder to it. You might be able to do that with a 2x3 holder as well. The hard part is getting the focus plane of the film the same as that of the ground glass.
Another option is to find a 2x3 Graflok back that can be mounted on your Color Scout if the slotted back is removable. Good luck and let us know how it goes.