Happy Cake Day @VexTeamZ, also that is help ful but VexIq gears are really thin.
Not exactly what you are looking for, but still a shaft coupler nonetheless…
I know. Clamping shaft collars (without the 12 tooth metal pinion) could be used, and so can high strength gears (I would not recommend this one). (Or you could just buy the longest length and cut it to your desired length).
Another way to join shafts together is using the 2x2 Center Offset Round Lock Beam 228-2500-1925. From a prior post:
The good news is that we included 6x of this part in the new 2nd generation 228-8899 IQ Education Kit, and another 4x in the 228-7597 2nd generation IQ Competition Spare Parts Kit. Any new VIQC teams that buy the complete 2nd generation IQ Competition Kit would get 10x of this part.