and the relationship of Rin and Archer is very similar to what happened to Eri and Harima. (Master and Servant) they're personality are closer too ^^
Master summons the Servant with similar personality (the exception was Rider which shared only some ideals with Shinji - hatred to all living beings, but she wasn't so vain and over confident).
Shinji doesn't have a match in SR... nor does Rider. Shirou and Suga looks the same but they have different personalities. Yakumo would be a great Sakura, but she would need to be raped by her brother
Tenma as Taiga !!
Itoko as Caster !! (but who would become Kazuki-sensei ??)
Max would make a good Gilgamesh and Harry good Lancer (Lancer is great, the greatest trio-team in game - Rin X Shirou X Lancer)
so here a black lagoon parody: