New and on a multi-site mission... I think

Well, I've taken a few peeks around the site and the forum and am interested... now just need to figure out whether a solution awaits.

Let me preface everything with the usual disclaimer... no CMS background, little PHP background, but strong background on XHTML/CSS table-less design.

I'm actually on a mission, in that I have some very specific things in mind, and would like to determine if Drupal can fit the bill, but also get some advice on where to begin and what things to look at specifically to my mission.

I want to develop a site that can offer theme related hosting/site solutions. Similar, though different topics, to something like Hostbaby. Targeted at the non-webbie person... not just newbie, but those who really have no desire to learn to make a site, they just want control over it. I've looked at a number of site builders, but I think they miss the mark for my idea and would overwhelm the target audiences.

So, as a designer, I want to develop a number of template themes, controllable thorugh CSS, and allow my users to select their theme, and then have an interface to add, update, and manage their content, without worry of messing up their site or the template. This way, they get a professionally designed look, though not exclusive to their site, but at a fraction of the cost of a custom site. Ideally they would be able to have their own domain name (which I could also provide if needed) and hosting space, however I realize that this may have to be a directory or sub-domain setup and use URL-framing. Obviously one of the goals is to have one central control area and the ability to provide various features (guestbook, calendar, gallery, etc.) to the users rather than setting up separate instances of Drupal which would become a nightmare to maintain. The other big issue is limiting the users control and visibility to just the things they need to control their content and to keep from overwhelming them.

I'm trying to grasp the multi-site functionality of Drupal and the templates, but still trying to determine whether what I am wanting to do is stretching things too far and in ways that just aren't doable.... if I'm trying to fit the square peg in the round hole, I'd just as soon keep looking to see if I can find a round peg or a square hole!

I haven't even installed Drupal yet, so my apoligize if this is asking too much, but I'm not asking for anyone to walk me through a complete setup and how-to, just looking for some kind of thumbs-up or down on suitability, and maybe a push in the right direction.

thanks for any thoughts, comments, suggestions, etc.