I have a Burley Bossa Nova with Suntour Front Skewer. The rubber piece on the acorn side (not the lever side) is showing some crazing / cracking. I am thinking about replacing the skewer. Are there special skewers for tandems or does skewer work? Also, are there special lengths for the front fork of a tandem?
The slight deterioration you describe isn't likely to cause problems. But if you're determined to replace the skewer, one designed for a standard single-bike is almost certain to fit. Borrow one from another bike in your garage (or from a friend or neighbor, if you don't have a single with QR wheels) and try it.
Is the rubber part just an o-ring round the acorn body so that your fingers grip better, or is it part of the bits that grip the wheel? If the latter it's not worth the risk of failure and definitely worth replacing.