[akeruu]

There are but I could not find many details about them in English. Some of the well knowns are:

すもももももももものうち or ははははははははのははははははとわらった

Please see MeCab (https://en.wikipedia.org/wiki/MeCab) segmentation output below:

http://www.edrdg.org/~jwb/cgi-bin/mecabdisp?sent=%E3%81%99%E...

http://www.edrdg.org/~jwb/cgi-bin/mecabdisp?sent=%E3%81%AF%E...

[glandium]

Mecab fails miserably on the second. It doesn't find the hidden "母は", but it's hard to blame it.