Since we cover almost every little change that Google makes, why not cover this. I have been hearing reports both at WebmasterWorld and via email from Tom and on Twitter that Google is showing now a main listing with two (not one or five) indented results.
Here is one picture of what I mean:

Normally, Google will show a maximum of one indented results. More recently, Google was showing a single indented result with a plus box to five more.
I believe this double indented result is fairly new and more and more people will begin to see this.
Forum discussion at WebmasterWorld and thanks to Tom and David.

Comments:
Michael Martinez
10/20/2009 05:52 pm
They've been doing this for a couple of weeks. They are also showing forum sitelinks for listings below the first one, too.
Peter Handley
10/20/2009 05:53 pm
When I've seen these today, there have been 12 results on the page, so the indents appear to be behaving not unlike site links. Also the font size on the indents has seemed slightly smaller than the main listings
Stefano Gorgoni
10/20/2009 09:00 pm
i'm seeing this since a week or so, but it seems to me it only happens when query includes brands/domain name...
No Name
10/21/2009 08:40 am
Anyone got any more examples? Not seeing many in the UK.
Kaushalaminc
01/07/2012 12:33 pm
Yes, Stefano - I also believe that in most cases this happens when domain or brand name includes in the query.