Because each article in ThemeMin has distinct/separate elements for header, content, and footer and because content height varies—there is not a way that I can see to move the "Leave a Reply" comment text below each post. That said, there's always more than one way to solve a problem in CSS. :)
I gave moving the article header elements around in their current space a try and came up with this. Try it out and see if it gets you a little closer to your end goal:
.entry-title {
padding-right: 100px;
}
.entry-meta-wrap, .featured-wrap {
position: absolute;
}
.post-comment {
position: absolute;
width: 110px;
left: 580px;
top: 0;
border-bottom: none;
border-top: none;
}
.entry-content, .entry-summary {
padding: 1em 0 0 0;
position: relative;
}
#page .entry-title {
padding-left: 0;
}