Stumped On How to Get Drupal to Jump Through This Hoop

Hi everyone. I have a site at www.ismyfix.com that I would like to move to Drupal so that I can allow users to create their own content. The crux of the problem I am running into is that I would like each subdomain off of the 2 main domains (ismyfix.com/aremyfix.com) to present different default content to a given user but the same user content. Imagine the left side of the screen changing by subdomain but the right being a default or user configured section which stays the same. Drupal has a single domain bias which seems to be pretty tricky to get around. I've looked at the subdomain module as well the mysite module and it seems like they are close but not quite. (Either that or I don't have enough experience to see how they would pull this off.)
Any ideas on how I can do this? I wondered if a .htaccess file with mod/rewrite for the subdomains to subdirectories would work but then my brain locked up when I tried to think it through! I really don't know. Is this particular project better done with CAKE or some other framework? The current site is pretty ugly and more of a proof of concept than a beta... I find it a bit embarrassing but it shows the direction of the concept pretty well.
Thanks for any thoughts you have time to share.
Korak