I did some searching on the old internet and as close as I can come to an answer to the question, "Who invented the Y2K fly" would be
David Knowles of Arkansas. Here is a link to a video of a tyer demonstrating that egg pattern. In reality this fly pattern has been used for many years, often by gear fishers just possibly not given a name or maybe it is just because the name refers to a period of possible trouble, the name stuck with the fly.
http://www.youtube.com/watch?v=K_qM_8v5XBI

Larry ---sagefisher---