[TeMPOraL]

Never used Maya, but what you describe sounds like something that's common in CAD software. I imagine this was spearheaded by AutoCAD and is a natural consequence of using Lisp as the underlying command/extension language :).

Two other applications that may be structured similarly are GIMP and Audacity (the audio editor). I say may, because I never looked under the hood to check on the internal architecture, but both also ship with an embedded Lisp interpreter for automation and extension, that integrates deeply with the tool's features.