With all due respect, not really sure what kind of research you are searching for?
It's common sence that there is usually only 2-3 QB's worth taking so early in the draft. (1st round) and most teams are either set at QB for a good 10 years or HC prefer to go after veterans since they do not have the time to develop a QB for fear of loosing their job.
Sure, I could use my rocket science powers and throw together a statistical layout with standard deviations and such, but I think football knowledge will suffice.
From today, look at the number of teams that are basically "set" at QB for atleast the next 5 years.
Arizona Cardinals - Kevin Kolb (yes)
Atlanta Falcons - Matt Ryan (yes)
Baltimore Ravens - Joe Flacco (yes)
Buffalo Bills - Ryan Fitzpatrick (yes)
Carolina Panthers - Cam Newton (yes)
Chicago Bears - Jay Cutler (yes)
Cincinnati Bengals - Andy Dalton (yes)
Cleveland Browns - Colt McCoy (yes)
Dallas Cowboys - Romo (yes)
Denver Broncos - Tebow??? Orton??? (maybe)
Detroit Lions - Stafford (yes)
GreenBayPackers - Rodgers (yes)
Houston Texans - Schaub (yes)
Indianapolis Colts - Manning (barring a non-injury recovery (yes))
Jacksonville Jaguars - Gabbert (yes)
KansasCityChiefs - Cassel (maybe)
Miami Dolphins - Henne?? Moore?? (no)
Minnesota Vikings - Ponder (yes)
New England Patriots - Brady (yes)
NewOrleansSaints - Brees (yes)
New York Giants - Manning (yes)
New York Jets - Sanchez (maybe)
Oakland Raiders - Palmer (maybe)
Philadelphia Eagles - Vick (yes)
Pittsburgh Steelers - Rape burger (yes)
San Diego Chargers -Rivers (yes)
San Francisco 49ers - Smith (maybe)
Seattle Seahawks - Jackson/Whitehurst (no)
St.LouisRams - Bradford (yes)
Tampa Bay Buccaneers - Freeman (yes)
Tennessee Titans - Locker (yes)
Washington Redskins - Grossman / Beck (no)
So basically from the current NFL teams there is basically,
3 Teams that desperatly need a QB.
5 Teams that maybe need a QB.
Which falls into the 2-3 QB's taken in the first round a year.