Here's an update on the blog profile. It now supports themes. The first theme I've made for it is based on Nikola's Futura admin theme:
http://processwire.com/blogtest/?theme=futura
I've also made a ProcessWire theme, but I think it still needs work (a little too girly right now):
http://processwire.com/blogtest/?theme=processwire
I'll probably put in one or two more themes for the distribution version. You can select the theme from the homepage. It's just a page reference field where it lets you select from pages using the "theme" template. The "theme" template is nothing more than a files field with all of the theme's assets in it. Typically this would be a CSS file(s), JS file(s), and images or font files (if used). I also had color pickers for defining the themes colors, but backtracked on that. I want themes to be self contained so that can create a new "theme" page, drag a ZIP file into the page, and be done with it. Once color pickers get involved, it becomes much less portable. Though I may still provide the option for overriding theme colors, but I have a feeling most people would prefer to just edit the included CSS file and then drag it back in.
This version also is better optimized for mobile use. In addition to converting the top navigation to a <select> in mobile views, it now moves the search box and any other navigation to the bottom. That way people on mobile should still see the primary page headline and some of the copy without having to scroll.