You guys have convinced me; it's doubtful the ebay bike was Major Taylor's.

More interesting to me than the bike is the man himself. Seeing the ebay auction prompted me to Google Taylor, and I found that he and his wife had a daughter during the 1904 Australian tour, and they named her Sydney because that's where she was born. Sydney Taylor Brown died in 2005 at the age of 101. Her obituary shows she led a pretty extraordinary life:

Sydney Taylor Brown obituary

Sydney Taylor married Dallas Coverdale Brown, and they had a son, Dallas Coverdale Brown, Jr., who is a retired U.S. Army brigadier general.

Major Taylor's great grandson, Dallas Coverdale Brown III, graduated from Princeton in 1978.