As some of you may know, Limewire is written in the Java programming language. Up until version 1.4 of the Java platform, wich is still in beta, the ability to utilize the mousewheel is not present using pure Java. Limewire is based on version 1.1.8 of the Java platform, in order to ensure compatibility with a wide range of systems for wich the newest version of the Java platform may not be available. If a mousewheel feature was to be implemented, it would require writing a native library (for each platform), and integrate it into the Java application using JNI. This is not impossible, in fact that is how the taskbar icon we Windows-users see has been implemented. Maybe they will take the time required to do this, but it is more likely that they will focus their attention at the core functionality, rather than on a secondary feature that is not directly related the file-sharing problematics.

/Tom Andresen
(I'm in no way associated with Limewire, and what you have read is just my personal theory.)