Hmm, you could probably pull this off..
First, we would hide the default copyright footer:
.site-footer .site-info {
display: none;
}
And then, using GP Hooks, add something like this to the “Before Footer” area:
<footer role="contentinfo" itemscope="itemscope" itemtype="http://schema.org/WPFooter" class="site-info">
<div class="inside-site-info grid-container grid-parent">
<span class="copyright">Copyright © 2014</span> · <a title="GeneratePress" target="_blank" href="http://generatepress.com">GeneratePress</a> · <a title="Proudly powered by WordPress" target="_blank" href="http://wordpress.org">WordPress</a>
</div>
</footer>
Then, of course, you can edit the inside of it to match your needs.
Let me know if this works or not 🙂