I find it interesting that when Katie Holmes was originally rumored to be playing the love interest "named Rachel." Fans thought that this meant Rachel Caspian, a character from Barr and Davis's "Batman: Year Two" and believed Nolan to be adapting Year Two. When Viggo Mortensen was mentioned by Michael Caine as being approached for a villain role, people thought that Mortensen would be The Reaper, the Year Two villain (obviously, that wasn't the case).
But could Rachel Dawes (originally Dodson) have kept the name Rachel Caspian from the comics? Well, they certainly don't look alike. They don't have the same occupation- Rachel Caspian wants to be a nun. And Rachel Dawes certainly doesn't have a father prowling the nights as a psychotic street vigilante with hooks for hands.
But there are similarities:
1. Both Rachels are concerned with the poverty and the evil in the city and seek to stop it. Their concern as well as their actions further attract Bruce to them.
2. Both Rachels hate the persona that Bruce Wayne has. Neither of them truly buys it. Rachel Caspian tells Bruce, "I've seen the real Bruce Wayne...not the playboy, nor the philanthropist..."
3. Both Rachels reject Bruce towards the end of the story.
4. Minor, but in both BB and "Full Circle" (the follow-up story to "Year Two") Batman gives Rachel a sedative to knock her out before bringing her back to shelter. Both of them later wake up in their bedrooms (in Caspian's case...her bedroom at Leslie Thompkins's place).
4. Here's the big part that I found interesting. This is in "Full Circle" by the way. In both BB and "Full Circle," Rachel responds to Bruce with something that Batman later repeats back to her. Instead of "It's not who I am underneath, but what I do that defines me"...
BRUCE WAYNE: Are you happy?
RACHEL CASPIAN: Perhaps we can never have exactly what we want, Bruce. I've learned to live with that. I'm content. That's more than many people have.
Just as the BB quote relates to the story, this quote relates to the theme of "Full Circle" about being able to let go of the past and remain satisfied with the present.
Anyways, Batman repeats it right back at her when she kind of recognizes him.
RACHEL: Tell me...do you know Bruce Wayne?
BATMAN: Not well. Why do you ask?
RACHEL: I as just wondering...is he happy?
BATMAN: He's content, Miss Caspian. That's more than many people have.
And then he leaves...to throw Joe Chill's gun into Gotham Harbor (oh yeah..)
Anyways, these may not have been intentional, but they certainly are similarities between them that would've been enough, IMO, to have had the character named Rachel Caspian.