I hacked up Wesley Hwang-Chung's webcomic plugin so it uses tags instead of categories to identify comics. Also lets you opt to put latest webcomic not at top of cover-page, but wherever it belongs in there chronologically. Lets you display all webcomic, the latest/strict (as in, only the latest of all entries that have at least the comic-tag), or the latest/relaxed (the latest of all entries that have only the comic-tag; entries that also have other tags are considered mixed text/illustration and displayed normally). Comic-navigation more themable. Comics-mode now also applies when browsing by-tag and selecting the comic-tag.
I hacked this up last night, so it's possibly broken six ways from Sunday. It seems to work for me; if it doesn't or I need more stuff, I'll fix it; otherwise, you're on your own. Consider this unsupported, do with it as you please (within the limits of whatever the license of Wesley's original version was, I guess), and have fun.
Here's the archive.
http://www.azundris.com/hacks/php/
Here's my brand-new comic I fixed it for. Yes, I'm rusty on the drawing front, only just got my replacement tablet. No, I don't seriously expect you to understand the punchlines.
http://katze-mit-wut.azundris.com/plugin/tag/Nu