How can I see full server request to track suspicious requests? I have very bad luck with spammers. Even though I employ both reCAPTCHA, Spamicide and BOTCHA, I get about one spammer per day, though 300 are blocked. I guess that's a pretty good ratio, but it still justifies me having to manually authorize new user accounts.

My website gets about 30K requests per day (as per access logs) of which 500 are POST requests. It runs on Drupal 6, though we are soon moving to 7.

I want to be able to see what the spammer sends when they make the request. Ideally, I would like to see the reCAPTCHA challenge they saw and what they wrote down. I'll be good with only the postdata, though.

Is there a way to achieve this using triggered rules? Is there a module which will allow me to do so (i.e. send the full request to log/email?)
I can't think of a module that would do this for all the different anti-spam modules. I know that the CAPTCHA module implements this for its own fields.

An alternative is a simple custom module that implements hook_form_alter to target the the desired form, adds a new submit handler to the form and store the submitted information using watchdog.