Terrell Suggs is done for the season, leaving a huge hole for the Ravens. The Ravens did offer a second round pick for Osi in 2011.

Reese has mentioned that all options are open for Osi, certainly trading the disgruntled player is on the table.

The question is, will Baltimore's need (and they are desperate) be enough for Ossie to offer enough to get a deal done?

This is a deal that makes sense. There is definate need, there is definate interest. The question is for how much?

Not opposed to making a deal happen but like you say, "how much?"
If it is a first round draft selection then probably. If it is a second rounder than probably not.
A second round pick is unlikely able to impact in such a way that Osi can for one more season.

Considering both GMs are good at getting good value.

I could see something like Osi Umenyiora for Paul Kruger and a conditional 2nd to 4th round pick (depending on 2012 production).

Kruger is a LB, but he is a better fit as a 4-3 DE imho; he is in the last year of his rookie deal. Kruger's 2012 salary is $615k.

Considering the Ravens have Courtney Upshaw and Sergio Kindle, they have the pass rushers to develop for the future. What they need is an impact pass rusher right now.

I could see the Ravens parting with a 2nd not a 1st. Honestly I don't see the need unless Kindle can't play. With Kindle, McAdoo, Upshaw, and Kruger I think they'll be fine.