Elon already said Starlink is not going public for a while because it doesn't have the cash flow yet. Ackman said on BLOOMBERG TV that Stripe & Airbnb said they were not interested in using his SPAC. Patrick and John Collison have both been very anti going public and so I doubt they will have a change of heart. They also have voting control of the company.
The only real possibility is Bloomberg LP, although Bloomberg had denied the rumors.
It's also funny that everybody seems to forget about Valeant and Herbalife...