I guess I might as well get into the naming game too. =0)
Simply "Lumia" with one letter to represent a line, along with one number to represent generation, and a maximum of one word following the letter/number to denote special features (such as dual sim).
e for the entry level phones (5XX and 6XX lines)
m for mid range phones (7XX and 8XX lines)
s for shooter phones (1020 replacement)
t for top-line phones (9XX)
x for phablets
Then you could have additions like DUAL, L, MINI, SPORT, METAL for extra features such as dual-sim, larger screen, smaller screen (4"), water-resistance, metal casing.
So Microsoft's offerings could be something like
Lumia e1
basic 4.5" screen, no dual sim
Lumia e1 DUAL
Same as e1, but with dual sim
Lumia e1 L
same as e1, but with a 5" screen
Lumia m1
730/830 style phone
Lumia s1
1020 successor
Lumia t1
920/930 successor
Lumia x1
1320/1520 successors
AND TO NOTE, I have tried to keep up on the thread, but if someone already said this same naming system, I apologize!!