Radioshack should carry variable resistors. They are called potentiometers or trimmer pots. They more than likely won't be with the regular resistors. I know I've purchased them there. Search radioshack's website for the one you are looking for and see if it says it is available in stores...
Did anyone else notice that the hotfix dnottis posted is supposed to enable CrossfireX in Eyefinity setups? Can anyone confirm that it works?
Edit: Didn't notice that the link was dead. We'll see when it actually is posted.
Does anyone have any performance tests of the 5770 in a 3150x1680 Eyefinity setup? I have yet to find any real data. Will it be respectable, or should I not even bother?