[caw]

This sounds like a good plan to hopefully learn something, if you can find someone. I don't know if you will though. How many websites out there have bad copy and the ability to critique you with specific links to what you're doing wrong. If that person knows so much about copy, to be able to identify the problem, google and find a source (or have one bookmarked), then why is their copy bad enough that they need you to fix it?

I don't think you'll have a problem with feedback should you do this. I think you'd have a problem with specific explanations. If you find you have no responses, you may try editing that bit out.