Great thanks! The comments manager is just what I was looking for. To make it it a bit more integrated I just moved the "Comments Manager" page from /admin/setup to /admin/blog, which doesn't seem to have caused any problems.
A couple of things: to get widgets from the sidebar to display on non-blog pages, the module has to be called on every page:
//CALL THE MODULE - MarkupBlog
$blogOut = $modules->get("MarkupBlog");
I've just added it to the top of my sidebar.inc for the time being, I'll have to refactor my code a bit in the future to stop it being called twice on blog pages. Second, to get posts to show only an excerpt, in the template files change the line:
$content .= $blogOut->renderPosts("limit={$limit}");
to
$content .= $blogOut->renderPosts("limit={$limit}", $small=true);
Currently it looks like the excerpt length is hardcoded to 450 characters - perhaps adding an option for people to set this themselves would be a good idea? In the meantime, for anyone that wants to change this, find the line
$summary = strip_tags(substr($page->blog_body, 0, 450));
in MarkupBlog.module and set it to whatever you want.
Great work, I'm getting more impressed the more time I spend with it!