I have just now "finished" a beta version of a YAML port for our little blog engine here.
A little information in advance for those of you who are not familiar with YAML: It is a great (X)HTML/CSS based framework optimized for maximum browser compatibility. It is not exactly a template but rather a set of various templates which can be customize to fit one's own needs. It's developer, Dirk Jesse, has put great effort into creating a very flexible, highly compatible framework which features basically every browser hack known to man
Therefore, it also features a wide range of cascading stylesheets, all of which are at the moment still included in my port. I plan to reduce them and the images included to those actually needed for the template, however. I should probably check with Dirk if that's okay or if he wants all YAML files included, which would make the final zipfile a little bit of a heavyweight.Unfortunately for those of you who don't speak German, the complete documentation for YAML is in German - at least as far as I can see. So if you're interested in how it exactly works its magic, you'll probably have to figure it out by studying the code, I'm afraid.
So there is a post in the German part of this forum asking for a YAML port for s9y. Markus Hagge, a German blogger, has kindly presented the YAML-based template he uses for his own blog, which of course is already customized to his own needs. So I decided to do a port which is rather 'generic'.
I chose three of the many layout choices YAML offers in order to cover the standard 3-column and 2-column (left sidebar or right sidebar) layouts. Right now, the template looks exactly like the YAML website, but I do not intend to change that - YAML is a framework, which in my humble opinion means that it gives you the very basics of the layout, but every user should customize the looks to fit their own wishes. I did, however, already adapt it to s9y, meaning I includes a seperate stylesheet 's9y.css' which covers s9y-specific styles. I also included some .tpl files (taken from the forthcoming 3.1 default template I did with Carl) to give the template CSS-only comment and contact forms. I also tweaked the layouts a little bit in terms of column widths since I think the standard widths in YAML don't fit too well for blog style.
The template is not yet ready for s9y 1.1, but I plan to add that later. Since I don't plan to include colorsets, this will probably mean that the 1.1 features will be a navbar which can be customized from the admin frontend and maybe optional coComment support. (Other ideas welcome, of course
)Oh, and of course you want to have a look at it in action, right?
I have switched my blog to this template. If someone wants to test it in their own blog or development blog, there is a zipfile, but remember: it's still beta 
However, it would be great if someone could check this out in different environments - I have checked all layouts with Firefox/Linux and Opera, no problems there. I have yet to check the differents IEs under Win, and it would be great if someone could check all this on a Mac. All this should work, but I'm not exactly sure whether my adaption to s9y messed something up ...
Here's one issue I've already found but not yet managed to fix: If there is an entry which only holds an (media manager) image, the footer is floated around this image. This could be fixed by adding 'clear: both;' to .serendipity_entryFooter, but this sometimes 'stretches' the entries. I'll try and set up a demo article for this.
So, enough rambling. Let's hear what you guys out there think
YL
However, I suppose this will never be an 'easy-to-use'-template for beginners anyway - the (CSS) code is simply too complicated for people without any CSS knowledge.