I think if you are a four year senior coming out in the draft, nowadays that has to be looked at as a poor indicator of elite NBA success. The last couple of "great"(All-Star caliber or better) players to be seniors and get drafted was I believe Brandon Roy in 2006 and Danny Granger and David Lee in 2005.
Highest drafted seniors in recent drafts
2011 - Jimmer Fridette (10th), Kenneth Faried (22nd)
2010 - Trevor Booker (23rd), Damion Jones (24th)
2009 - Terence Williams (11th), Tyler Hansbrough (13th)
2008 - Jason Thompson (12th), Roy Hibbert (17th)
2007 - Acie Law (11th), Al Thornton (14th)
2006 - Shelden Williams (05), Brandon Roy (06), Randy Foye (07), JJ Redick (11), Hilton Armstrong (12), Rodney Carney (16)
Hibbert actually applied for early entry into the draft as a junior but withdrew. He was talked about as a potential top ten pick and some mock drafts had him going ahead of his teammate, Jeff Green.