The hard part is finding people to organize it who have enough time, patience, experience, and willingness to do it. LeapBack took 9 people to come together and make it happen. They worked tirelessly for over a year lining things up, taking trips out to California to setup and verify things, courting actors and other special guests to appear. And in the end, those friendships were tested to the breaking point and became adversarial at the end. It's just an incredible amount of work.
I know there were some attempts to start one a few years back by someone personally funding the event through craft sales rather than the standard channels, reservations, and ticket sales.
To have another Quantum Leap con is going to either take someone with deep pockets or someone doing all the same work that was done for LeapBack. Actors came to that event because it was a non-profit and nobody got rich off of it. It was handled professionally and seriously with the right connections and attitude so that actors and agents were willing to say Yes. A typical promoter-run con would not have attracted as many people as LeapBack did, or would have to have paid huge appearance fees which could not be recouped with the number of tickets a Quantum Leap-specific event would draw.