In this related answer a combo is mentioned that involves using Great Cleave and Whirlwind Attack together to get extra attacks from cleave by killing things with whirlwind attack.
However I do not see how this could work since Whirlwind Attack specifies that:
When you use the Whirlwind Attack feat, you also forfeit any bonus or extra attacks granted by other feats, spells, or abilities.
Was this combo just a thought experiment that did not actually work by RAW or am I missing something in this interaction?
Not since the 3.5 revision
That's the post 3.5 revision of the feat Whirlwind Attack (Player's Handbook (2003) 102). The original 3e version of the feat (that can be found with some searching here) lacked that warning and had this benefit:
Thus the original feat's benefit tacitly encouraged hauling around a bag of rats to facilitate many, many attacks against the big bad by those PCs who also possessed the feat Great Cleave.
While the feat goes unmentioned in the Revision Spotlight Web column (consolidated here), as a reader of the Wizards of the Coast forums during the pre- and post-revision process, many assume—as do I—that the changes made by the revision to the Whirlwind Attack feat were a direct response to the Bag of Rats Issue.