OK...I figured it out. I was just too far ahead of myself...I was thinking I'd need to create the models, handlers and drivers for my content type when all I really needed/wanted was to create a content part and then create a new content type using
that part. I basically just did this:
ContentDefinitionManager.AlterPartDefinition("MyCustomPart", builder => builder
.WithField("MyCustomFieldName", fieldBuilder => fieldBuilder.OfType("MediaPickerField"))
//Create the content type...
ContentDefinitionManager.AlterTypeDefinition("MyCustomContentName", cfg => cfg
I was just making it way more complicated than it needed to be...now I just need to add Orchard.Fields to my list of dependancies in the module.txt and I'm good to go I think...