EditorialGuy - 1:59 am on Sep 6, 2013 (gmt 0)
I haven't seen that format, but I just saw a really attractive single text ad: It was a leaderboard with a light grey background, a large all-caps headline in blue sans-serif type, and one line of large text (black sans-serif type, upper and lower case). Just to the right of the headline and text was a circle with a stylized arrow in it. When I moved my mouse over the arrow, the circle's internal background changed from light grey to charcoal.
The design is unquestionably the nicest-looking AdSense text ad that I've ever seen.