This is surprisingly difficult to search for, so I'll ask though it may be a silly question. Is it possible to chain several model-builder models in sequence, such that one will automatically run with the precondition that a prior model has executed? There are plenty, so it seems more sensible than a merge, but I would be interested in that as well.
I'm going to try… gp.AddToolbox("c:/mytoolboxes/tools.tbx") gp.ModelName() or gp.ModelName_ToollName() (or vice versa, not sure), and make sure that the toolbox has an alias. With the script-tool in the toolbox, drag and drop to the model and link (or use precondition? it doesn't use any input variables). That should run another model.