I have two dogs, one is a black lab/ heeler mix and the other is a Rot/basset hound mix. The lab, Leeroy, we had for about a year before we got the weirdo mut, Ollie. Leeroy has horrible separation anxiety. When we leave he tears the hell out of the yard, barks, cries, and is a general terror. Tried using the crate when we left him to see if it would help and all he did was bust out of the crate and destroy that too.
After getting the second dog it has seemed to help him a lot. He still has moments of tearing crap up and i guess that is somewhat to be expected. I think it helps to try and keep them occupied. A new bone, or something that they can chew on to keep them busy. Another dog in my case. I never have tried the medication but i have heard good things about it. I just don't trust it for some reason.
I have a Siberian Husky that was very similar. Tried to crate train and she mangled her face trying to get out. Put her in the back yard and she'd flip out, destroy everything, knock over her water and almost be dead when we got home. Tried to tie her up (which we hated) and she almost hung herself, literally.
After doing some research, which I should of done in the first place, I found out how their breed were pack dogs, like most, and felt more comfortable with other dogs around. So we went to the SPCA and got another dog and it worked like a charm. We left them both inside together, since that's where the husky was most comfortable, and they just chill out all day.
Now, she still has moments, but its nothing compared to what it used to be. We also invented the term "dog-a-rize", which is what needs to be done before we leave the house. Shut all the doors, pull up the blinds (replacing blinds 3 times throughout a house that has 20 windows is NOT fun!), put a chair in front of the pantry and put the cat food on top of the fridge. Essentially eliminate any option for bad behavior. It becomes part of your routine.
My parents turn on the tv and radios throughout the house so their dogs can "hear human voices all day". I think its totally bogus (and costly), but to each their own.
I agree both with giving them something to be their favorite toy and something new to keep them distracted and entertained. Our dogs love kongs frozen full of peanut butter and it keeps them going for awhile. We had to get rid of one of our dogs and the one we still have took some time adjusting to that change. We gave her more attention and she seems to be ok now.