Wells Fargo has tweaked the design of its Student LoanDown blog by adding a comment input box for the most-recent blog post (see inset). The bank uses this a similar technique at its first blog, Guided by History.
This should spur more comments, especially with the call to action at the bottom, "send a comment to Barbara." Users preview their comment, and read an onerous Wells Fargo disclaimer (see second screenshot below), on a separate page before submitting.
The comment input box is only used on the first blog entry on the main page. Late entries revert to typical blog format, with the comment function at the bottom of the post.
The main downside to this layout is that it's a bit distracting (see screenshot below), but that's probably a good trade-off if it helps drive more comment activity.