Are there any other dogs that suffer from separation anxiety and how do you overcome it?  What are they signs?

Hit there, all breeds of dogs can suffer from separation anxiety, it is not restricted to Weimaraners.  The way to prevent separation anxiety from occurring is correct "alone" training from Day 1 so that the puppy regards as being left as nothing horrendous and is a normal part of every day life. 

Owners often unwittingly train their dogs to be anxious in their absence because they encourage the dog to follow them about all over the house, sit on their laps, feet, sleep in their beds etc and the contrast between this and when you have to go out for a couple of hours is too much for them and they cannot cope.

Having a crate and stairgates etc helps you to make sure that puppies are separated from you from the beginning eg when you need the toilet, shower, to cook etc.  It will be nano seconds at first, then seconds, then minutes until you can safely leave your dog alone for up to 4 hours which is not unreasonably long.  One of the ways to prevent SA is to give something to the pup/dog that it gets at no other time such as a filled kong so that it looks forward to separation rather than the reverse.  Also cool departures ie not making an event of leaving; also never return to a dog whilst it is actually making a noise etc but the moment it is quiet and calm, hence why you must train in incremental steps.

Alone training is a vital part of rearing a competent and confident dog;

The signs of TRUE separation anxiety are many and varied depending on the dog, they can and do include either alone or in combination: howling, barking, scratching, drooling, destruction etc.

It is something that is easily prevented and much more difficult to treat.

HTH