Theres some excellent issues in play here.
First off, a deal for Harvin as mentioned (for a draft pick) is exactly what led to us to have few draft picks in the past couple years and have some very expensive veteran players.
You can say "there is no one of harvins skill level in the 2nd round" and you would be 100% correct, but that isnt the way the NFL works. If you trade for Harvin you are also trading for the right to PAY him a big contract. What would a 2nd round pick in the 2013 draft be worth if they made $8 million a year instead of $1.5? Trading a pick for harvin, for a team in the jets situation is not smart team management.
Now the better question would be what about looking to the vikings for a deal for Revis and have harvin included? Now that "contract risk" is taken out of the equation as you are trading on 2014 UFA for another. The Vikings have $9 million attached to antione winfield that comes off the books after 2013, so they could in essence use that money for Revis in 2014 and "lessen the contract blow".
Or, even better for the jets, what about sending Cro straight up for marvin? Again we lose the contract risk as Cro comes off the books, we keep our draft picks, and since we are also in a similar position as the vikings (at WR not CB) holmes will come off the books for 2014 and we can use that money to pay harvin and then be able to hoepfuly still sign revis.
The vikings are a very interesting trade partner, and they can say what they want, but where theres smoke theres fire and harvin and the coach (who they like a lot) do not get along. However trading a draft pick for a 1 year rental who we then have to pay big money to is definitely not the way to go.