I was considering starting this thread myself, but you have saved me the effort
It looks like most of the squad have been named. I won't include all the squads, but here are some of the top sides:
South Africa:
Chris Dry, Schalk Brits, Frankie Horne, Kyle Brown, Branco du Preez, Cheslin Kolbe, Justin Geduld, Cecil Afrika, Bryan Habana, Seabelo Senatla, Cornal Hendricks, Warren Whiteley
The South African squad has been posted elsewhere, but I will include it here, as it is the most interesting squad. On paper it is a very exciting squad, with Habana, Brits, Whiteley, and Hendricks all excellent XV's players (Hendricks has a strong 7's pedigree too), Horne, Dry, and Brown are all experienced forwards, and between du Preez, Geduld, Senatla, and Kolbe there is more than enough pace and elusiveness in the backs! I understand that there is still a concern about whether Habana and Brits will be released to play. While on paper the team is incredibly exciting, personally I feel that XV's and 7's are very distinct games these days, and transferring between the two games is not as straight forward as it may have been in the past....
England:
Dan Bibby, John Brake, Mark Bright, Philip Burgess, Mike Ellery, Charlie Hayter, Christian Lewis-Pratt, Tom Mitchell, Dan Norton, Tom Powell, James Rodwell, Marcus Watson
The only surprise (to me) in the England squad is the inclusion of New Zealand loose-forward Mark Bright. He was always a good player while in NZ (I felt he was very unlucky not to get a Super Rugby contract), but given his age (he's 35!) I'm somewhat surprised he has made the England squad.
Australia:
Ed Jenkins (capt), Liam Gill, Sean McMahon, James Stannard, Greg Jeloudev, Cameron Clark, Jesse Parahi, Tom Cusack, Sam Myers, Con Foley, Tom Lucas, Pama Fou
A relatively stable squad, with the only new inclusions being Liam Gill and Sean McMahon. I thought they were showing some good signs towards the end of the World Series, so should be a big threat in Glasgow
New Zealand:
Pita Ahki (North Harbour), Scott Curry (Manawatu), Sam Dickson (Canterbury), DJ Forbes, captain (Counties Manukau), Bryce Heem (Tasman), Akira Ioane (Auckland), Gillies Kaka (Hawke's Bay), Ben Lam (Auckland), Tim Mikkelson (Waikato), Declan O'Donnell (Waikato), Sherwin Stowers (Counties Manukau), Joe Webber (Waikato)
New Zealand have resisted the urge to include many Super Rugby players this time (Ben Smith, Gear, Guildford, Messam etc went to the last Commonwealth games), with the only Super Rugby player included being Pita Ahki (who is hardly a big name...). They have stuck with the same side that has been successful this season, though it is interesting to see Declan O'Donnell making a reappearance after a couple of years struggling with injuries. Basically it is a side full of 7's specialists - apart from Ioane, Ahki and possibly Webber I don't expect to see any of these players at Super Rugby level in the future. It is interesting to see that two of NZ's most experienced 7's players - Tamasi Cama and Lote Raikabula - missed out on selection, though both will be travelling with the side as the two squad reserves.
One of the real features of this NZ side is the size of the players. 8/12 players are around (or over) the 100kg mark, with only a single player listed at less than 90kgs (Webber at 88kg). Overall there isn't a lot of pace in the side, they will be relying more on solid defense, good team work, and strong play at the breakdown rather than individual pace / elusiveness.