Darko/Hawes/Justin/possibly Watkins would be quite the young big man group...
Take a look at the teams, starting spot at PF or C, oppurtunities (touches and time to develop), and team situation:
Hawks - they have Horford, Pachulia, Shelden, Smith, Marvin. Could get him if they move 1-2 guys? I don't know, maybe.
Boston - Al Jefferson, Perkins, Big Baby, Gomes. Have become a win-now team with Ray/Pierce, and being in the weaker east.
Bobcats- Have the cap-space, and could be a starting big slot open, but not for sure with what's been talked about by Vincent. They have Okafor, Hermann, May, re-signing G-Wall eventually. With the situation of the team now (3 seasons in the league, improving each year, and players improving well, front-office feelings), and getting J-Rich, they're a playoff-ambition team now. They would of kept B. Wright if they didn't feel that way yet. No.
Bulls - Big Ben, Tyrus, Noah, Gray, veteran PF. Tyrus or a veteran PF will be the starting PF. Still need an inside-scorer, but are a win-now team. Even if Darko was going to be the starter he wouldn't get the PT because of the other big men. Also Deng sees some time at the 4 when going small, Nocioni as well if he's brought back.
Cavs - Gooden, likely Varejao, Illgauskas, Marshall. Finals, title-hunting team. Need a legit wing-scorer and 6th man for LBJ anyway.
Dallas - No.
Denver - No.
Detroit - Would be ironic, but they do lack a center, problem is they're still gonna be a title-chasing team. Re-signing Billups.
Warriors - No. They're trying for KG supposedly anyway.
Houston - Houston are in win-now mode, and want to go deep in the playoffs. Would they be willing to develop Darko? Adelman's not a young players coach, given his history with Gerald Wallace/Kevin/Garcia/Price. Darko also wouldn't have a top role there, despite starting (I guess), because of Yao/T-Mac/Bonzi/James all commanding shots. Not sure Houston would be a good fit for Darko, despite lacking at PF outside of Chuck Hayes. A veteran like Joe Smith, PJ Brown, Marc Jackson, Webber seem like a better fit for the Rockets, and next to Yao.
Indiana - JO could stay or be dealt, regardless, still have Diogu, Muprhy, Foster. Don't quite think so.
Clips - No.
Lakers - No. Win-now team, and have Bynum, Odom, and are chasing quality veterans.
Grizzlies - Lack at center, and have Gasol, but not sure what they want to do as far as direction. Also are going after Nocioni and Varejao.
Heat - No.
Bucks - Doubtful. Mo Williams, Yi, Bogut.
Minny - If they deal KG it'd be for B. Wright and/or Biedrins. Still have Mark Blount, and KG if he's not moved, which can really happen. They're either a win-now team or a rebuilding team. That's kinda questionable right now. Ultimately would say no.
Nets - Playoff team, finals-chasing team. Krstic, will chase after veteran big man. Just re-signed Carter.
Hornets - Nope.
Knicks - No way.
Magic - Don't think so.
Sixers - Definitely a possibility. Darko could go next to Dalembert, they need a good PF.
Suns - No.
Blazers - No.
Kings - Legit possibility. Very nice fit next to Hawes, no set starter at PF. Need a good young PF like Darko.
Spurs - Nay.
Sonics - Negative. Iffy location situation, Durant, Swift, Green, Wilcox, Collison, Sene, Petro. Too many people

.
Raptors - Need a center (though Rasho is serviceable), but they have Bosh, Bargnani, and are a younger win-now team. I doubt it.
Jazz - No.
Wizards - Doubt it.
Darko could well have to settle for the MLE.
One of SAR/KT, will be dealt for sure, IMO. Most likely SAR. Brad I don't know.