For posterity purposes, here are my predictions about who the Broncos might actually pick in this year's draft. As I see it, I don't think free agency will likely have much of an impact on the possibilities.
Three things rule the top of the draft: Money, projected impact, and money.
Because the top 10 picks cost so much money, teams pick players that are expected to have the largest impact. This puts an incredible premium on the biggest impact positions: QB, LT, pass rusher, and, to a lesser extent, CB. Take the best prospects at these positions, plus a few players at other positions who are such good, can't miss (remember the money) prospects that they can be expected to have a big impact even from those other positions, and you've got your top 10. Unless you're the Raiders, there is too much money on the line to think outside of the box this high in the draft.
Let's look at this year's draft:
QB: Bradford and Clausen
LT (the safest pick, and thus the most likely for teams to reach for in the top 10): Anthony Davis, Russell Okung, Trent Williams
Pass rusher: Jason Pierre-Paul, Derrick Morgan
CB: Joe Haden
Can't miss at other positions:
DT: McCoy and Suh
S: Eric Berry
MLB: Rolando McClain
G/C/K/P: Not enough impact to ever get picked in the top 10.
Wildcard, the best potentially elite, but not a sure thing WR/RB: Dez Bryant
That's 13 players, and 10 of those will be the top 10 (plus potentially one crazy Raider pick). And I'd be willing to bet that the Broncos will pick one of the three that are left at number 11.
At least 1 QB (Bradford), 2 LT (Not sure which two), 1 pass rusher (Pierre-Paul), 1 CB (Haden), and 2 DT (Suh and McCoy) are definitely off the board by the time the Broncos pick.
So the potential options for the Broncos are 1 QB (Clausen), 1 LT, 1 S (Berry), 1 pass-rusher (Morgan), 1 MLB (McClain), and 1 wildcard (Bryant)
They are not going to take a LT or Clausen (though I do think they would take Bradford if he was available). I don't really think Morgan will be available. I'm putting him here because a lot of mocks appear to have him dropping that far, but pass-rushers are always at a premium, and he's a good one. I think they will take McClain if he is available. The only tough choice is between Berry and Bryant (and everyone seems to think Berry will be gone, so this will probably be a non-issue. I only put him down here because I think his position is not that highly valued). I think this puts them in the same situation they were in last year, choosing between the wildcard Moreno and Orakpo. Because they already had a stud at Orakpo's position (Doom), they went with Moreno. Because they already have a lot of talent at S, they might do the same thing this year. But I would take Berry (and Orakpo last year) because they are surer things.
So, realistically, barring trade, the Broncos will pick McClain or Bryant. I would be shocked if they picked anyone who was not on this list. And I think there is a really good chance McClain drops to the Broncos because his position is one of the least valued of any of these top prospects and he is not as sure a thing as Berry.
If you're going to argue for Iupati or Pouncey, I think you've got to make the argument that they are the best guard or center prospect of all time. Because guards and centers just don't go that high. They don't have the same kind of impact and they don't make that kind of money. Plus, if we do take into account free agency, I would again be shocked if the Broncos don't come out with a solid guard or center to put alongside Olsen. While right now those appear to be the positions of greatest need, I doubt they will be by draft time.