Hey! I found this short interview Ashley did on the internet recently. Actually.. like 5 minutes ago! Well anyways, here is the interview an direct link:
MEDIA: This movie really sets up Sharpay to return to East High should there be a High School Musical 4. Will you be coming back for another installment?

[laughs] I don’t know anything about that. It is flattering to have an open door, obviously, for my character. But I am doing other projects as well and moving on. But this project is something I’ll always hold close to my heart. We have so much fun. We’ve created such an amazing family, and I have the best time on and off screen with this cast.

How emotional was it shooting the final scene?

[Director Kenny Ortega] had said this amazing speech, and that’s what got us all going. And hair and make-up [crew members] even started crying. [laughs] That was an emotional-fest. But you know, Lucas Grabeel…He’s such an amazing person, and is very, usually, stand-offish in feelings. He doesn’t show his feelings. And he even teared up. And that’s something that’s really big. Because the last three years…I mean, he’s “the man,” you know? He doesn’t do that. But he showed some tears. And it was definitely emotional. [laughs]