I feel for you. I too have furry family members who lack opposable thumbs.
Also though, I can offer this advice: Check shelters from surrounding towns as well as those local (and vet clinics and dog parks and pet stores are a great place to put flyers since other pet owners often take in strays). My moms dogs went awander one day and none of the local shelters had them and they hadn't turned up at the door whining for dinner either. Oddly enough, after several days of futile searching, I had a dream that showed me both of them sitting in a kennel at a shelter after discarding the notion that they could be at a shelter that was over a 45 minute drive away.
The next day I drove down there; sure enough that's where they were, and almost ready to be adopted out since the hold time was over on that day. I didn't realize the shelter could be so far from where they were actually picked up, but the way the county/city zoning is drawn, they fell under the other jurisdiction and got schelpped pretty far after getting picked up pretty close to home. If someplace is too far to drive to easily you could also call, but it's better to check it out first-hand if you can, though I wouldn't have found them at all were it not for that prophetic dream. ( and I'm convinced it was my pal who passed on who sent me the 411 - great dog, he was. Lassie had nothing on him; never heard of her barking out "Timmy's in the well" from the great beyond!)
Good luck. (and I'll send a mental message to my buddy to send you some inspiration if he knows where to find her =D)
Afterthought: My boyfriend lost his rottie once when he was still a pup and managed to locate him by talking to the local "rent-a-cop" security patrols that do rounds through the neighborhood doing drive by checks on subscribed houses (Westec, or what have you, you know the kind I mean?) Since they are already making the rounds, he figured it wouldn't hurt to ask them to keep an eye open for his dog and it proved to be a winning strategy. After a bit, one of the guys drove back and told him he might have found the dog, but he wouldn't come to him. He had to take Chad over to where he saw him and he was there hiding in the bushes all scared and timid, but even Chad didn't see him at first. He came bounding out with much relief after Chad peered in and called him, though. Good call on Chad's part, though. Those guys might not think anything of a dog they see unless someone has brought it to the front of their mind with something specific to associate, and they cover a lot of ground. Its worth a shot.
Also how old is she? You mention that there are other dogs also who remained behind and only she was gone? Not to be a downer, but we had a couple shepherds who both took off when their time came, and I understand that it is common for dogs to try to leave when they feel death is imminent. One we never did find (he was notorious for escaping anything, but usually turned up after not too long on his own except for the last time). The other only made it as far as the neighbors lawn before succumbing to old age, leaving a legacy of a number of holes dug in the yard sometime during the night when he had never been a digger before. With that in mind, we tried to honor what we assumed to be his last wishes and buried him in the yard despite the laws which prohibit it. If she was not usually a runner, this might be her way of sparing you the pain of her death. Don't give up hope, though. I do hope she turns up no worse for wear, it was just something that bears mention.
