There are 2 major strategies for responding to such a difference:
1. Vector scaling. It will make the difference irrelevant and the resulting UI will look approximately the same on whatever a resolution.
2. Capacity scaling. I.e. keep the same font letting more information to fit in the control without scrolling.
It may be a little bit hard to formalize but these two can be combined intelligently. It is also important to know which one the user prefers (e.g. I mostly prefer the second while many prefer the first).
Why? What else is there? I'm actually curious. I personally have never dealt with displays bigger than 1280x1024.