http://ronpaulgraphs.com/nov_5_extended_total.html
From the look of the graph, the line appears too even for too many hours straight.
It appears to me that it's possible that they are running up against some limit in the donation system. It doesn't appear to be bandwidth, possibly something in the back-end system that actually handles the donation processing?
I guess maybe we'll find out later, but it would be highly disappointing if there could have been even more donations, but they were held back by limitations in the donation system, thus preventing the campaign from setting a historical record in Presidential campaign donations for a 24 hour period.