There are threads at Google Groups and DigitalPoint Forums with multiple reports of Google not crawling Blogger hosted blogs, that are on custom or private domains (i.e. not on blogspot.com domains). Many have reported that the Googlebot crawling has stopped as of July 30th.
I asked Branko to help me see any pattern to the issue and we found a couple things. Both domains listed in the thread have similar patterns.
(1) They both have a robots.txt file that blocks a Google crawer, Mediapartners-Google. Now, we know that Google uses multiple crawlers to index content and they all work together. Branko theorized that maybe that "reduced frequency due to reducing the number of spiders that visit his site." I agree, that is a possibility.
(2) This is more striking to us, is that if you view the source code of both of the reported blogs, you will notice a widget from a script named SetSystemMarkup. I am not sure what that widget does, but in the widget, it has NOINDEX,NOFOLLOW in it. Maybe Google is misinterpreting that as a META tag? I do see that these blogs are both in the Google index, but maybe this is impacting any recent crawl activity for these sites.
I do not think this is a Blogger or Blogspot.com wide issue.