I guess Nvidia / AMD graphics card style naming might work the best. Product name (Xeon, Pentium, whatever), #generation digit, 1-3 digits of entry/mid/premium level. Like Celeron 120 (generation 1, premium level 2(0)).
Right now non-technical people seem to be still expecting i6 and i8 CPUs.
i7-720: "7" was the performance tier, "20" the generation
So an i7-820 was the same generation, but a higher performance tier, and the i7-940 was yet another higher performance tier and a later generation.
They've later switched to a 4 digit numbering scheme which is decipherable, but not nearly as clear as the 3 digit scheme. The introduction of quadcore i5s and dual core i7s really muddled the waters.
The i7-720, i7-820, and i7-940 are all Nehalem (ie first generation) core parts.
The numbering more or less makes sense if you prepend a 0 to the "720". Now your generations make perfect sense.
Current desktop product codes still more or less make sense. Mobile is a complete clusterfuck though.
Then there's the branding as Pentium or Celeron...