This is the prop I used in my sketch "Sh0rtcut", which you can see here:
Honestly, the quality of the portal gun is above the video itself, which had a number of compositing issues. I hope to see others utilize it better than I did!
The gun is fully rigged for animations, and there is a convenient driver setup which allows you to select/transition the color of the portal device from the blue or orange setting. Included is also the setup of the light streak I used. Though its rig is not the best and it could look more dynamic, it makes for a good starting place. In the final sketch, note I added extra "glow" and "rippling"in compositing to get the final look of the light streak.
Moo-Ack! ~Patrick W. Crawford