You're bound to run into confusion when you have (a) too many cameras simultaneously on the market, (b) when you release cameras too rapidly. The EOS 100D came out in 2013 ... it's an "entry-level" camera, so the EOS 150D should be here this year, as well as the 750D ... what happens in 2017 (the new 300D) and 2019 (the new 100D or 1000D or 000D)? Plus, eventually the 5D and the 1D series will reach Mark L and even more eventually Mark C level. But before then, there'll be the Mark XXXVIII and, fitting for the 1D series, the Mark XL.
You forgot about the 100D/SL1. What will happen to the x0D line after the 80D and 90D?
After the 950D the rebels will likely go back to 300 and after the 90D the xxD line will likely go back to 10 but they might not be "D". Although I am curious as to what the 100D / SL1 will become. Maybe 110D?
Well at one point it becomes useless to add the 'D' to designate 'digital'. Better drop it and use an 'F" for film or something like that
5D3, 5D2, Sony α6000, G16 | SY14 f/2.8, Ʃ20 f/1.8, 24 f/2.8, 35 f/2, Ʃ35 f/1.4A, 50 f/1.8 I, Ʃ50 f/1.4 EX, 100L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 2.0x III, 70-300L | E-mount: SY12 f/2, 30 f/2.8 EX DN, 16-70 ZA OSS, 55-210 OSS, Metabones SB | FT-QL, AE-1P | FD(n) & FL lenses