Unfortunately I am one of ‘those guys’ who are very tied to Microsoft products. My company is a Microsoft Certified Partner and we have always used their products. I am sure that I could figure out Linux, but the learning curve might take a while.
Yes, all of the CMS programs that I have tried use Linux and are able to generate ‘friendly’ pages, but only with Apache or other web servers.
Same with Mambo. Xaraya, I have gotten up and running, but also uses the .htaccess file which IIS doesn’t appear to make use of. In fact, in Mambo when you try to enable the ‘SEO friendly’ feature, it screws everything up. 
I would venture to guess that Xaraya does the same.
I checked out Drupal (which I had previously not used) and it is the same.
I may be SOL and have to start learning a new system!
All my servers are Win2003, though (with IIS). Makes it difficult.