aliasing a domain name to a URL path in another domain without a redirect

I would love to hear about it if anyone can anyone think of a way to achieve the following:

I have a customer who is interested in doing cool stuff with targeted advertising. He wants me to take a new domain he's acquired, e.g. specific-term.com and point it to a page on a drupal site (with clean URLs on and path aliases/redirects on), e.g. general-site.com/specific_term - that's not too hard, but here's the twist: do it without a redirect.

I've been able to set up an apache2 rule like this (in my apache virtual hosts file):

  ServerAdmin webmaster@general-site.com
  ServerName specific-term.com
  RewriteEngine on
  RewriteRule ^/(.*) http://general-site.com/specific_term [L,P]
  ProxyRequests On
  ProxyVia On
  <Proxy *>
    Order deny,allow
    Allow from all
  </Proxy>

The above alias works, in that if someone enters the URL http://specific-term.com they get the content on the page http://general-site.com/specific_term ... Problem is, as the page loads, the URL changes (the browser gets a 301 redirect) thanks to Drupal's devilishly clever built in clean URL and URL aliasing functionality. So what I want to do is figure out a way to leave the target page, http://general-site.com/specific_term, working as per normal if the user gets to it via that URL while at the same time

• allow the user to reach the same content without a redirect (301) on http://specific-term.com
• have internal links on the page ideally continue to use the http://general-site.com domain

I think this will be pretty tricky, if doable at all... I've thought about using a static page copy of the content at http://general-site.com/specific_term and making it the DocumentRoot for specific-term.com but that becomes hard to maintain, and I've had problems in testing it with the dynamically included CSS provided by modules - they error with the wrong mimetype according to firebug...

Any thoughts would be most appreciated!

Dave