There -- I've now beaten my LJ style into some kind of shape. Colors are the kind of mix I like, with dark backgrounds for the surrounding bits but light for the reading bits. I've taken the built-in Tabular Indent template and fixed the obvious bugs. (The colors for the headers in the comments page were oddly hosed due to a couple of typos, and it had structured the HTML such that Mozilla doesn't use the correct foreground colors in the comments. More importantly, I've tweaked the entry boxes so that the Subject always shows up on top, which I strongly prefer; the built-in template shows the header fields in random order.)
Template hacking turns out to be pretty easy: S2 is enough like Perl to be pretty intuitive. (Although the C# geek in me is appalled at the apparent lack of a "continue" statement.) Anyone who knows HTML and Perl reasonably well should be able to pick up S2 quickly.