There have been a number of requests to build cues longer than the standard 58 inches.
This can be done but there are a number of negatives. 1. You can’t try one before you buy and you may not like the way it plays after it is finished. 2. Long cues won’t fit in standard cue cases. 3. There will be significant additional cost versus a standard length cue.
A cue extender as shown below is a low cost alternative which minimizes most of the negatives. They fit between the existing butt and shaft and can be made any length for any standard joint configuration. The sample is 4 inches long and happens to be for the popular 5/16 x 14 joint. Cost would be about $50.