Gary, Your post contains a lot of the ideas being tossed around here in this thread, so I chose it to reference from.
I also think that (1) lid for multiple pots/cups would be a really smart move for a gear company. It would allow them to produce a line of pots, including a cup; for single person use (cup), smaller pot for short trips, larger pot for extended trips. If you brought all three pieces along on an outing the lid could be interchanged as needed during the meal.
Having the MSR Titan myself, I'd make this design the larger pot and work back from there, getting squatter as you go. It's a fuel efficent shape, and packs well amongst other gear. The only caveat I have found with this item is that the area that holds the handles on can be sharp and cut fabric.
Interchangeable set of handles would lower the set's weight too. Or a bail, ala Bill F', would also suffice IMO. I think a bail offers the added advantage of easier conformation of a cozy, without danger of the handles tearing it. Plus, the bail stays far enough away from the flames to stay cool to the touch(if it can be made to 'lock' in the upright postion, like the Titan's lid handle)IMO.
The only thing I differ on here with others is the fact that I prefer pots/cups without any internal rivets, markings, or indentations. I use a packtowel or viscose piece to wipe out my cooking gear after use; because I have found this not to scratch the interior surface. I once had a pot with 'measurements' scribed inside and found it impossible to clean out food crud. If the measurements were on the exterior, and did not interrupt the smooth interior surface that would be useful. I think most folks can eyeball the correct level of liquids from the outside, since markings should be a good inch or so apart. After using certain pots and cups over the years I've found it easy enough to Sharpie mark the exterior to my satisfaction for measurement usage IMO.