Latest update regarding this situation:
Although it's been recently said that Soriano had a "1/2 of 1% chance" of being traded, that now it looks very likely TEX will deal him by Sunday, according to things I've picked up that's been attributed to sources close to John Hart and the Rangers. The three-way trade including the Reds is still being floated around and there are several variations of it; some of the names I've seen linked to the Reds in some fashion or another include John Hudgins, Juan Dominguez and Adrian Gonzalez from TEX and Aaron Heilman, Jae Seo, Brian Bannister, Royce Ring and Victor Zambrano from NYM. Obviously, not all these names will be involved if something does indeed happen, but they are the names I've seen tossed around in different variations of it. Some of the players have even been linked as going to different teams in different variations (for instance, Heilman is going to TEX in some versions, CIN in others). I would think with NYM taking on all that salary (with both Soriano and Casey on the books for next year; not just "rentals" for this year), they would probably try to include Zambrano in the deal to one team or the other, to at least get some of the cash burden off their shoulders a little, though they would likely be dropping Cameron's salary in a potential deal.
I don't see Adrian Gonzalez being involved. There may be some thought that if he's involved, NYM might just as soon take him instead of Casey for 1B and save the payroll a little. The Reds probably wouldn't acquire him in the potential deal because if they were to move Casey, it would finally solve the outfield glut problem, unless they turned around and dealt one anyway, which is possible. Then I could see Gonzalez involved in going to CIN. Truth be told, if Adrian Gonzalez gets dealt in the coming week, I would actually expect it to be to BAL, as the Rangers have shown interest in taking Sidney Ponson from the O's now that the Nevin trade as officially fallen through.
Anyways, back to the topic at hand. Luckily, the Mets seem to be seeking a high average guy, and that's why they are pretty high on getting Case. If it goes down as a three-team deal with these three teams, I could see it working as something along the lines of this:
NYM gets: Alfonso Soriano, Sean Casey
TEX gets: Mike Cameron, Yusmeiro Petit, Victor Zambrano (maybe Royce Ring or Jae Seo also)
CIN gets: John Hudgins or Juan Dominguez + Aaron Heilman
I'm not saying this will happen, just saying, I could see something like this work out if it goes through as a three-team deal. Lots of crazy stuff could happen in the next few days, so we'll have to stay tuned.