I think they look very clean and simple. They seem on the narrow side (not that that's a bad thing at all!); were you aiming for a nice look on mobile devices?

Actually no. It does look pretty good in mobile Safari, though.

The problem is I have so little content to work with at this point. I'm sure I could make up some content, but without all the modules to add content and fluff, I'm stuck with a registration form, a login form, and a logged in page.

It is very narrow but, with my screens being at 1024x768 and 1366x768, it doesn't actually look too bad IMO. As I add modules and such and build the site up, I'll implement the latest 1100px-width design.

PLEASE no wider than 1024px minus window decorations. The vast majority of people still use 1024x768 (I don't, but I still occasionally use OTHER computers).

Default width is 1000px
Just looks better at 1100px

Just depends on your resolution

What about backups and data transfer?

For instance, most of this isn't CMS specific but adding in a how-to is a pretty good plus I'd imagine.

Accessing the CMS MySQL via OpenOffice Database or other Database Program for off-site raw data editing, and a button to compile a backup for download (or/and even a second MySQL Database) and to restore.

I remember when you and rivereye made the same plea to me about Cemetech6, hence why it can find of 1024x768 screens.