If Twitter for blackberry allowed editing your retweets then I'd be down. My only experience is on a 9700 though.
You can edit on Twitter for Blackberry. It's not the retweet feature, it's "quote tweet". I don't know why RIM chose that, but it can be done.
I use both UberTwitter and T4BB. Both have their pro's and con's. Overall, I prefer UberTwitter. I'm still using them on my 9700. I haven't decided if I'm going to get the Torch or the 9780.
