thanks for the response.
In shownote, indentation is done with nested <ul>s. There is no <li> for the content, though, which is illegal. I'm not sure about the compatability of any of the easy workarounds -- could use a li type=none, haven't done any research into how compatable that is.
or you could use style sheets instead of nested uls.
wasn't aware of the htmlnest option, i'll check it out. also wasn't aware of the reliance of everything being patched. as diotalevi pointed out below, we probably won't get posts in xhtml format--that's a fair point. but i think xhmtl 1.0 transitional is still pretty forgiving--note the transitional in the moniker. i don't expect the site will validate on every page, but newest nodes (and other pages where it's possible) should be valid something, in my opinion.