Some things I disagree with.
1.) Drew Brees with 30?

No matter what way you attempt to spin it, this number is absurd. This is an offensive line that gave up 41 sacks all of last season- with a pro-bowl center anchoring the line and a pretty darn mobile QB. Not to mention that Jamaal Brown has looked bad at tackle thus far and that they have had very little time to gel as a unit. Nesbit was moved to LG just a few days ago. How can you expect decent protection with all the shakeup?
Id be surprised if a.) Brees isnt knocked out for some time and b.) if they dont end up top-5 in sacks allowed this season.
Points I considered were Brees had 27 in 05 and 25 avg career behind a line some consider worse. In a new system with new OL, I bumped him up to 30. With the developements you've mentioned, perhaps more bumping is in order.
2.) Peyton Manning at 15. Yes I do realize that you project him to play 13-14 games this season and this number, while certainly doable, is probably not very likely. For one, while the Colts did not have any losses on the o-line, every team in the AFC South has either retained their pass rushing DE's or have upgraded (Mario Williams, Brent Hawkins (who is a stud

). Also, while Addai is supposedly as sure as they come in terms of pass-blocking IIRC, he missed a few assignments during the Rams game. Or was that Rhodes?
I tended to look at the QB getting rid of the ball and the consistant oline. I felt Peyton and his solid cast
would be able to account for the things you've mentioned. The question I would pose then is, do you think Peyton will be able to be close to his 13 sack avg and get rid of the ball to Wayne when he has a little less time due to better pass rushers and missed assignments? Bump accordingly.
3.) Daunte Culpepper at 40?

Being a bit harsh on the Miami O-line arent we? This is a unit that was bottom 5 in sacks allowed with 26. But 40?

They retained all their key elements (some of which were injured in 2005) and even swayed Houck from the Chargers. Perhaps the most encouraging news is the fact that the AFC east has lost one of its key pass rushers in Abraham and IIRC, they are switching to the 3-4 . If anything they do better than they 26 they allowed last season. Expect saban to adress this issue with the highest regard-he knows he must protect the injured Culpepper in order to make a run.
Although CPep was sacked at a rate that would have resulted in 71 sacks last year and a 45 carreer avg, I felt his recovery from injury and Mr Houck would overcome switching to a new home. I could go 30's.
4.) Brett Favre at 30?

Again, The GB line is full of questions but is unquestionably worse off than last season. Wahle and Rivera gone? Spot starting two rookies? Ill pass on that action. They could be abused this season and posting the ~30 sacks allowed like last season would be improbable if not impossible.
What can I say, a pick isn't a sack. With an avg of 29 career sacks, Brett is experienced in getting rid of the ball. Thier schedule should be easier this year, but you have a point, that line may not be able to keep him from early retirement.
5.) Steve McNair at 25. Again Im going to have to disagree on this. This is a unit that will battle injuries and was not able to adequately protect their QB last season. If Ogden has a bad season/injury expect things to go rapidly downhill. You have them ranked as one of the best units in the game and that simply isnt true anymore.
25 is about his avg, but you've pointed out the potential bad side of his line. I agree he could slide, but this is where I see him now
6.) Brad Johnson at 26.

Sure Hutchinson is a god at his position and they are getting back Birk but to cut their sacks from last season down in half? Again, its plausible but I dont think its doable. Even when their line started to get it together they still averaged >2.5 sacks a game under BJ. Coaching may shake things up further. As much as Tice is a joke, he still knew how to get the best from his line.
***Also applies to Chad Pennington. Will two good rookie plugins be able to cut down their sacks close to half?****
Line upgrades, easier schedule and this is about average for Johnson. I don't know if he could take more than that. Pennington same sans schedule bonus.
Other than that you have a few guys within reason that may be a bit of a stretch. Nothing that blows me out of the water like the above but I may have overlooked things. Good to see you doing this on your own. I applaud the effort.