Here are other 1st round wide receivers who were taken in the first round and were under 6'1" since 2002.
Donte Stallworth
Lee Evans
Santonio Holmes
Ted Ginn Jr. (the only drafted in the top 10)
Jeremy Maclin
Percy Harvin
You left a couple names off of your list.
Hakeem Nicks
Roddy White
If you go back another year, you can add Reggie Wayne and Santana Moss. All of the players you listed are also smaller speed receivers with return skills who weighed under 200 lbs at the time of their draft. Some of them well under. Blackmon is listed anywhere from 207-215. He's a different animal.
Additionally, 14 of the top 20 leaders in receptions last year are under 6"2". I think Blackmon could join them next year or the year after.
I don't believe any of them were taken top 10, in their 1st round year. (except Ted Ginn, Jr. who is a bust).