Well, 70mm only has two options, 2.20:1 (2001: A Space Odyssey, Lawrence of Arabia), or (with a special anamorphic lens) 2.76:1 (Ben-Hur). I do agree that IMAX's 1.44:1 is far too close to 'Academy' ratio (1.33:1). I've never been a huge fan of anything between 1.33:1 and 1.85:1 - 2:1 or higher is my personal preference, though 2.76:1 is pushing it a bit ...

I wonder what an anamorphic IMAX aspect ratio would be, or if that's even possible ... I doubt such lenses currently exist at all.