My staffy is 9 yrs old, normally a very happy, affectionate and quirky little girl, she became ill on Sunday 29/5/11) very suddenly... trembling, standing but not wanting to walk, abdomen tight and tender, very very pale and panting. Took her to emergency vet, temp was 39.5, they kept her in for 2 days and nights, I now have her back home but she is still very unwell, the vets do not know what's wrong with her... have done test after test but they still don't know. She's very very quiet, abdomen is still tight and clearly tender, she doesn't want to walk or move too much, temp goes up and down, still pale... temp went right up again last night so I rang the duty vet.. they just said "we've done all the tests", well I guess not as they don't know what's wrong with her.
She is not getting better... what can I do if the vet seems to have given up on her?

I would ask for the test results and take her to another vet.
Just like doctors, it always pays to get a second opinion from a vet as well.

The symptoms are very broad so I can understand why they are having trouble pinpointing the exact problem but I personally would seek out another vet.

I have taken my dogs to vets that have been recommended by people and they could not find what was wrong... I have taken them to a different vet for the same problem and they have been diagnosed right away and the problem remedied.

I guess the short version is: Seek a second opinion.

Thanks, I think that is my only option if the vet feels they have done all the tests.

Sorry I can't offer you much more.
Have they mentioned gas at all to you? One of my mothers poodles did have similar symptoms when he was partially bloating.
Bloat is when the stomach fills with gas and eventually twists, blocking off both exits. Some dogs get the gas without the twisting, it can be very painful which explains the panting and shaking.

That is only one theory though, there could be many other problems it could be.

Those symptoms of panting, shivering, reluctance to move, tender (very)and tight abdomen are classic for acute abdominal pain, or acute intervertebral disk syndrome. I would doubt she is interested in anything by mouth, either... like food or water. X-rays or ultrasounds may be informative, were any done?

I would be looking to eliminate a problem related to abdominal pain, and the most common is acute pancreatitis. In the early stages, the traditional lab results are misleading because they usually haven't had time to develop to diagnostic levels. Since most of these conditions are related to pancreatic infection, this may explain the temp spikes. Have you been given any medication at all?

Since this is a veterinary problem for solution, another vet may be in order, and it may be helpful to have a copy of her lab test before going, But, most 'other' clinics like their own tests, so be prepared to have another series done. This isn't simply to puff up he bill, because things change, sometimes dramatically and diagnostically, in a couple days.