However, I don't like new files as patches. I really prefer to have my device tree be a dts file that I bring in instead of bundled into a patch. Maybe I'm not following the guidelines, but I think it's nicer to be able to search for dts things in .dts files and I get nice syntax highlighting and whatnot.

This is what I do on custom boards. It's better to "look" at files and link to others when they're files and not patches.