I've looked a couple times and maybe I missed this, but does SS not have a template (html/css) editor built in to the CMS or as a module like wordpress or expression engine does?

ok, lets see if I can explain this a little better.

WordPress is a lot like SilverStripe in that they both have a main templating system. You can then create or reuse Themes for your site layout. The difference in the two is that WP has a section inside the CMS where you can actually modify your theme's code. It has an internal editor where you can physically edit the html and/or css and save it. Only to the theme files though, in case you want to add a widget to the sidebar, etc. You can see a listing of all the files that make up the theme, and edit them.

Ah. I see what you mean.
I'm quite sure there isn't such a thing for SilverStripe. It should be possible to write such a module, but I doubt the usefulness. Editing CSS/HTML is usually much more comfortable in a designated editor. And with a SilverStripe site, you usually also have access to the files (FTP) which might not be the case with a Wordpress installation. For content that's changing a lot, one can build editing capabilities inside the CMS without messing with the template files.

For people who want full site administration/modification possibilities via web-browser, such a module could be a useful thing though