After what seems like an eternity, we finally have movement in the player market. If there's any truth to the rumors that have been floating since the GM meetings about potential trading partners for the Braves, a couple of the recent signings and trades should begin to help Frank Wren limit his focus.
There have been separate rumors reported today regarding the two reportedly "available" trade chips at Wren's disposal. However, they haven't been connected (publicly, at least) in the same deal. Three-way trades are few and far between in recent years, but as we saw with the one the Diamondbacks, Tigers, and Yankees pulled off centered around Curtis Granderson, Austin Jackson, Ian Kennedy, Max Scherzer, and Edwin Jackson, they CAN be profitable for all involved IF the participating GMs have the chutzpah to follow through even if the deal doesn't seem like a clear "win" on the surface.
That said, I'll float my own three-way proposal, connecting several dots that have already been reported. The teams are the Braves, the Rockies, and the Reds. To find the logic may involve reading carefully, so adjust your glasses accordingly.
The Braves interest in the deal is somewhat obvious - a surplus of affordable starting pitching and a valuable player in Prado who's value isn't maximized since he's playing out of position as well as having to move around more than you'd like to move him. Prado "works" as a LF, fits as a "stand-in" for Chipper Jones at 3B, but "is" a 2B (and a good one, evidenced by his All-Star Game selection before the team acquired Dan Uggla).
The Rockies interest in Prado has been documented, and they want him to play at his best position for them. They have two commodities the Braves are looking for this winter - depth in legitimate CFs in the event the team can't re-sign Michael Bourn following this season (Dexter Fowler, Charlie Blackmon, and Tim Wheeler), and a legitimate Chipper Jones replacement candidate in Nolan Arenado who projects to be ready in time for Chipper's exit. However, Prado's not enough to convince baseball-savvy people to part with one of the CFs and Arenado, much less get Dan O'Dowd to pull the trigger.
Enter the Reds. They've made no attempt to hide the fact that they're looking for a SP, and they have a limited budget (like the Braves) to work with meaning C. J. Wilson and Mark Buehrle aren't on their radar. They've been repeatedly linked to Jurrjens, but there doesn't seem to be a match. They're also looking for a closer who will be less-expensive than the market seems to provide thus far. They have a "closer-in-waiting" in Brad Boxberger (much like the Braves did with Venters and Kimbrel when they had Billy Wagner), and a significant chip who seems to be "blocked" for the forseeable future in Yonder Alonso because they're reportedly going to try to find a way to extend Joey Votto. They experimented with moving Alonso to LF, but don't seem convinced he's going to be able to handle the move defensively.
Reports have the Braves looking for a return that is comparable to the one the Royals received when dealing Zack Greinke last winter, so here's one fan's attempt at a deal that would work for all involved.

The Reds receive Jurrjens and SP prospect Zeke Spruill from Atlanta, and Huston Street from the Rockies.
The Rockies receive Prado from Atlanta, and Yonder Alonso and 3B/OF prospect Todd Frazier from the Reds.
The Braves receive SS/CF prospect Billy Hamilton from the Reds, and CF Dexter Fowler and 3B prospect Nolan Arenado from the Rockies.

Jurrjens gives the Reds the inexpensive SP they're looking for. Street gives the Reds the affordable "bridge Closer" that Boxberger could serve as understudy to in 2012. Spruill gives the Reds a SP prospect with a middle of the rotation ceiling if not slightly higher given development.