I'm really curious about Blue's version exclusives.
While cleaning my room I found an old print-out that lists the non-obtainables in every version up to Crystal.
Red(English/Japanese): Sandshrew, Sandslash, Vulpix, Ninetales, Meowth, Persian, Bellsprout, Weepinbell, Victreebel, Magmar, Pinsir, Mew
Blue(English)/Green(Japanese): Ekans, Arbok, Oddish, Gloom, Vileplume, Mankey, Primeape, Growlithe, Arcanine, Scyther, Electabuzz, Mew
Blue(Japanese): Ekans, Arbok, Vulpix, Ninetales, Mankey, Primeape, Bellsprout, Weepinbell, Victreebel, Electabuzz, Magmar, Mew
Yellow(English/Japanese): Weedle, Kakuna, Beedrill, Ekans, Arbok, Raichu, Meowth, Persian, Koffing, Weezing, Jynx, Electabuzz, Magmar, Mew(English)
I was wrong about the Blue/Yellow possible link. With that you can't get Ekans, Arbok, Electabuzz, and Magmar...Close, but no cigar. So you can not complete Blue without at least 2 of the other games. That stinks.