don't. just please, if you love either breed at all do NOT do this. 1) no breeder who produces quality dogs is going to sell you a pup if you let them know you plan to do this. 2) you aren't going to get healthier dogs by doing this since many of the same genetic issues are in both breeds. Are you going to spend almost $2000 to prove that the 2 dogs are healthy enough to breed simply to produce pups that people can get at the local pound? 3) this mix and similar are in the pound by the hundreds 4) the coat would be the same since there isn't a lot of difference between lab/gsd coat type. Both have thick undercoats and shed it by the ton all year long.
You can find GSDs that are social like a lab and don't have the breed typical aloofness to strangers. You can even foster this desire to meet new people to a certain degree by simply rewarding your dog for seeking attention from strangers from a young pup.
My GSD is a therapy dog. He's not climb on your lap, bowl you over, happy to meet strangers like a lab but enjoys attention from his adoring public. Especially kids!
She died in Feb. 23, 2013, and Kalia was born March 21, 2013. We didn't know about her until May when we saw her on a rescue group's website, I emailed the lady, she said that she just so happened to be coming to New England in a couple of days with Kalia to bring her to another rescue up here, (from Arkansas) and if I really wanted her, as long as my references checked out, we could have her because she'd rather see her in a home than in a rescue. Two days later, we were picking her up from the meeting place...I really feel like she was MEANT to be ours, it worked out so perfectly for us, I was in such bad shape after Chloe died, and she saved me as much as I saved her. Perfect fit. 
