@McNultyHosting - Here are something things to chew on...
1. CMS systems tend to be on the bulky side when it comes system resources. A website owner who is building a community on the Drupal framework will quickly get too big for his shared hosting-britches. If you do not have a VPS, semi-dedicated, or dedicated product line for them to grow into, you would be setting yourself up to lose customers when they get too big.
2. From a consumer's perspective, I probably wouldn't give my business to a host that ONLY suggests they are a Joomla or CMS host. I would only consider them if they have a value proposition that is unique to the industry. For instance, I would only be impressed if:
A. Your web and database servers were specially optimized for my CMS system.
B. You offered no-charge support for CMS setup and configuration.
C. You had readily available technical support that could troubleshoot a problem with my CMS system if something broke (perhaps during an upgrade or module installation).
D. You offered CMS professional services that I could purchase at a competitive price.
From a consumer perspective, these types of value-added services are the only things that would convince me that you're truly a niche player.
B.S. - The Post Script of Brian Stevenson